Learn Go Programming

Go, also known as Golang, is an open-source programming language developed by Google. It is designed for simplicity, efficiency, and strong performance.

Go is used in web development to build scalable applications and APIs, in cloud services to develop microservices, and in DevOps to develop automation tools. It’s also popular for networking servers and large-scale data processing tasks.

Many companies need developers who know Go, especially for backend, cloud, and DevOps roles.

Check out API guides on Go programming: Golang Standard Library (Learn 500+ in-built functions).

Go Tutorial

• What is Go Programming?
• Setting Up the Go Environment
• Your First Go Program
• The Structure of a Go Program
• Go Comments
• Go Data Types
• Go Variables
• Go Constants
• Go Operators
• Go Arithmetic Operators
• Go Relational Operators
• Go Logical Operators
• Go Bitwise Operators
• Go Assignment Operators

Go Control Flow Statements

• Go If-Else
• Go Switch Statement
• Go for Loop
• Go for-range Construct
• Go goto Statement
• Go break Statement
• Go continue Statement

Go Functions

• Go Functions
• Go Recursion
• Go Closures
• Go Variadic Functions
• Go Anonymous Functions

Go Arrays and Strings

• Go Arrays
• Go Slices
• Go Command Line Arguments
• Go Strings
• Go String Functions
• Go String Formatting
• Go Text Templates
• Go Regex
• Go User Input

Go Packages and Modules

• Go Packages
• Go Modules

Go Types

• Go Struct
• Go Interface
• Go Pointer
• Go Reflect
• Go Rune Type
• Go Generics

Go Map

• Go Map

Go Error Handling

• Error Types in Go
• Go Error Handling
• Go Recover
• Go defer Keyword
• Go Panic
• Go Custom Errors

Go Concurrency

• Go Concurrency
• Goroutines
• Go Channels
• Go Channel Buffering
• Go Channel Synchronization
• Go Select
• Go Channel Directions
• Go Race Conditions
• Go Mutex
• Go Atomic Variables

Go File Handling

• Go Reading Files
• Go Writing Files
• Go Line Filters
• Go File Paths
• Go Directories
• Go Temporary Files and Directories

Go Networking

• Go Networking
• Go URL Parsing
• Go Base64 Encoding and Decoding

Go Time

• Go Time
• Go Epoch Time
• Go Tickers
• Go Time Formatting and Parsing

Go Programs with Output

• Go Program to Print Hello World
• Go Program to Add Two Numbers
• Go Program to Swap Two Variables
• Go Program to Check Even or Odd Number
• Go Program to Find the Factorial of a Number
• Go Program to Check if a Number is Prime
• Go Program to Generate Fibonacci Series
• Go Program to Find the Greatest of Three Numbers
• Go Program to Reverse a String
• Go Program to Check if a String is a Palindrome
• Go Program to Find the Sum of Elements in an Array
• Go Program to Find the Largest Element in an Array
• Go Program to Sort an Array Using Bubble Sort
• Go Program to Reverse an Array
• Go Program to Implement Binary Search
• Go Program to Find the Second Largest Element in an Array
• Go Program to Remove Duplicates from an Array
• Go Program to Merge Two Arrays
• Go Program to Find the Frequency of Elements in an Array
• Go Program to Find the Length of a String
• Go Program to Convert a String to Uppercase
• Go Program to Convert a String to Lowercase
• Go Program to Concatenate Two Strings
• Go Program to Reverse Each Word in a String
• Go Program to Count the Number of Words in a String
• Go Program to Replace a Character in a String
• Go Program to Remove Whitespace from a String
• Go Program to Check if a String Contains Only Digits
• Go Program to Create and Initialize a Slice
• Go Program to Append Elements to a Slice
• Go Program to Copy a Slice
• Go Program to Remove an Element from a Slice
• Go Program to Merge Two Slices
• Go Program to Iterate Over a Map
• Go Program to Add Key-Value Pairs to a Map
• Go Program to Delete a Key from a Map
• Go Program to Check if a Key Exists in a Map
• Go Program to Find the Length of a Map
• Go Program to Create and Initialize a Struct
• Go Program to Access and Modify Struct Fields
• Go Program to Embed Structs
• Go Program to Implements for a Struct
• Go Program to Compare Two Structs
• Go Program to Check if Two Strings Are Anagrams
• Go Program to Find the Longest Substring Without Repeating Characters
• Go Program to Find the First Non-Repeated Character in a String
• Go Program to Count the Frequency of Each Character in a String
• Go Program to Read a File
• Go Program to Write to a File
• Go Program to Append Data to a File
• Go Program to Check if a File Exists
• Go Program to Delete a File
• Go Program to Rename a File
• Go Program to Copy a File
• Go Program to Create a Directory
• Go Program to List Files in a Directory
• Go Program to Read a File Line by Line
• Go Program to Handle Errors with the Error Type
• Go Program to Create Custom Errors
• Go Program to Use Panic and Recover
• Go Program to Handle Multiple Errors
• Go Program to Implement Logging in Error Handling
• Go Program to Validate User Input with Error Handling
• Go Program to Count Digits in a Number
• Go Program to Find the Cube of a Number
• Go Program to Calculate the Employee Salary

Go Standard Library

• Golang Standard Library

Golang fmt Package Functions

The fmt package in Go provides formatting for input and output, offering a wide range of functions to handle strings, errors, and formatted I/O. Below is a list of commonly used functions in the fmt package:

Function	Description
Golang fmt.Append Function	Appends a formatted string to a byte slice.
Golang fmt.Appendf Function	Writes the formatted string to a specified writer with format specifiers.
Golang fmt.Appendln Function	Appends a formatted string to a byte slice, followed by a newline.
Golang fmt.Errorf Function	Formats according to a format specifier and returns a string as a value that satisfies the error interface.
Golang fmt.Sprintf Function	Formats according to a format specifier and returns the resulting string.
Golang fmt.Fprint Function	Writes the string to a specified writer, such as a file or an HTTP response.
Golang fmt.Fprintf Function	It reads from a specified reader and scans the input.
Golang fmt.Fprintln Function	Writes the string to a specified writer, followed by a newline.
Golang fmt.Fscan Function	Reads from a specified reader, scanning the input.
Golang fmt.Fscanf Function	Reads from a specified reader, scanning the input with format specifiers.
Golang fmt.Fscanln Function	Reads from a specified reader, scanning the input until a newline.
Golang fmt.Print Function	Prints the string to standard output.
Golang fmt.Printf Function	Prints the formatted string to standard output, with format specifiers.
Golang fmt.Println Function	Prints the string to standard output, followed by a newline.
Golang fmt.Scan Function	Reads from standard input, scanning the input.
Golang fmt.Scanf Function	Reads from standard input, scanning the input with format specifiers.
Golang fmt.Scanln Function	Reads from standard input, scanning the input until a newline.
Golang fmt.Sprint Function	Formats using the default formats for its operands and returns the resulting string.
Golang fmt.Sprintf Function	Formats according to a format specifier and returns the resulting string.
Golang fmt.Sprintln Function	Formats using the default formats for its operands and returns the resulting string, followed by a newline.
Golang fmt.Sscan Function	Scans the string for the specified formats.
Golang fmt.Sscanf Function	Scans the string for the specified formats with format specifiers.
Golang fmt.Sscanln Function	Scans the string for the specified formats until a newline is encountered.

Golang strings Package Functions

The strings package in Go provides functions to manipulate UTF-8 encoded strings. It includes various utilities for searching, splitting, trimming, and formatting strings. Below is a list of commonly used functions in the strings package:

Function	Description
Golang strings.Clone Function	Returns a newly allocated copy of the input string.
Golang strings.Compare Function	Compares two strings lexicographically.
Golang strings.Contains Function	Checks if a substring is within a string.
Golang strings.ContainsAny Function	Checks if any of the characters in a string exist in another string.
Golang strings.ContainsFunc Function	Checks if a string contains any characters satisfying a predicate function.
Golang strings.ContainsRune Function	Checks if a rune is within a string.
Golang strings.Count Function	Counts the number of non-overlapping instances of a substring in a string.
Golang strings.Cut Function	Splits a string at the first occurrence of a substring and returns the two parts.
Golang strings.CutPrefix Function	Removes the provided prefix from a string.
Golang strings.CutSuffix Function	Removes the provided suffix from a string.
Golang strings.EqualFold Function	Compares two strings for equality under Unicode case-folding.
Golang strings.Fields Function	Splits a string into substrings at each instance of whitespace.
Golang strings.FieldsFunc Function	Splits a string based on a custom function that determines where splits should occur.
Golang strings.Split Function	Splits a string into substrings separated by a specified delimiter.
Golang strings.SplitAfter Function	Splits a string into substrings after each instance of a specified delimiter.
Golang strings.SplitAfterN Function	Splits a string into N substrings after each instance of a specified delimiter.
Golang strings.SplitN Function	Splits a string into N substrings separated by a specified delimiter.
Golang strings.Title Function	Converts a string to title case.
Golang strings.ToLower Function	Converts all characters in a string to lowercase.
Golang strings.ToTitle Function	Converts all characters in a string to title case.
Golang strings.ToUpper Function	Converts all characters in a string to uppercase.
Golang strings.Trim Function	Removes all leading and trailing instances of specified characters from a string.
Golang strings.TrimFunc Function	Removes all leading and trailing instances of characters from a string based on a predicate function.
Golang strings.TrimLeft Function	Removes all leading instances of specified characters from a string.
Golang strings.TrimLeftFunc Function	Removes all leading instances of characters from a string based on a predicate function.
Golang strings.TrimPrefix Function	Removes a specified prefix from a string.
Golang strings.TrimRight Function	Removes all trailing instances of specified characters from a string.
Golang strings.TrimSpace Function	Removes all leading and trailing white space from a string.
Golang strings.TrimSuffix Function	Removes a specified suffix from a string.
Golang strings.Join Function	Joins a slice of strings into a single string with a specified separator.
Golang strings.HasSuffix Function	Checks if a string ends with a specified suffix.
Golang strings.HasPrefix Function	Checks if a string starts with a specified prefix.
Golang strings.Index Function	Finds the index of the first instance of a substring in a string.

Golang math Package Functions

The math package in Go provides basic constants and mathematical functions such as trigonometric, logarithmic, and exponential functions. Below is a list of commonly used functions in the math package:

Function	Description
Golang math.Abs Function	Returns the absolute value of a given float number.
Golang math.Ceil Function	Returns the smallest integer value greater than or equal to the input.
Golang math.Floor Function	Returns the largest integer value less than or equal to the input.
Golang math.Trunc Function	Returns the integer part of a float number, discarding the fractional part.
Golang math.Mod Function	Returns the floating-point remainder of the division of two numbers.
Golang math.Modf Function	Returns the fractional and integer parts of a floating-point number.
Golang math.Remainder Function	Computes the remainder of the floating-point division of two numbers.
Golang math.Round Function	Rounds the floating-point number to the nearest integer, breaking ties by rounding away from zero.
Golang math.RoundToEven Function	Rounds the floating-point number to the nearest integer, breaking ties by rounding to the even number.
Golang math.Copysign Function	Returns a number with the magnitude of the first argument and the sign of the second.
Golang math.Signbit Function	Checks whether the sign of a floating-point number is negative.
Golang math.Dim Function	Computes the positive difference between two numbers.
Golang math.Min Function	Returns the smaller of two floating-point numbers.
Golang math.FMA Function	Computes the fused multiply-add of three numbers.
Golang math.Exp Function	Returns the exponential value of the input.
Golang math.Exp2 Function	Returns the base-2 exponential value of the input.
Golang math.Expm1 Function	Returns the value of (e^x – 1) of the input.
Golang math.Log Function	Returns the natural logarithm of the input.
Golang math.Log10 Function	Returns the base-10 logarithm of the input.
Golang math.Log1p Function	Returns the natural logarithm of (1 + x) of the input.
Golang math.Log2 Function	Returns the base-2 logarithm of the input.
Golang math.Logb Function	Returns the exponent of the input number.
Golang math.Ilogb Function	Returns the exponent of the input number as an integer.
Golang math.Pow Function	Returns the base raised to the power of the exponent.
Golang math.Pow10 Function	Returns the value of 10 raised to the power of the input.
Golang math.Sqrt Function	Returns the square root of the input.
Golang math.Cbrt Function	Returns the cube root of the input.
Golang math.Sin Function	Returns the sine of the input angle.
Golang math.Cos Function	Returns the cosine of the input angle.
Golang math.Tan Function	Returns the tangent of the input angle.
Golang math.Asin Function	Returns the arcsine of the input.
Golang math.Acos Function	Returns the arccosine of the input.
Golang math.Atan Function	Returns the arctangent of the input.
Golang math.Atan2 Function	Returns the arctangent of y/x considering the sign of both arguments.
Golang math.Hypot Function	Returns the square root of the sum of the squares of two inputs (the hypotenuse).
Golang math.Sincos Function	Computes the sine and cosine of the input angle, returning both.
Golang math.Sinh Function	Returns the hyperbolic sine of the input.
Golang math.Cosh Function	Returns the hyperbolic cosine of the input.
Golang math.Asinh Function	Returns the inverse hyperbolic sine of the input.
Golang math.Acosh Function	Returns the inverse hyperbolic cosine of the input.
Golang math.Atanh Function	Returns the inverse hyperbolic tangent of the input.
Golang math.Gamma Function	Computes the Gamma function of the input.
Golang math.Lgamma Function	Returns the natural logarithm of the absolute value of the Gamma function.
Golang math.Erf Function	Computes the error function of the input.
Golang math.Erfc Function	Computes the complementary error function of the input.
Golang math.Erfinv Function	Computes the inverse of the error function.
Golang math.Erfcinv Function	Computes the inverse of the complementary error function.
Golang math.Float32bits Function	Returns the IEEE 754 binary representation of a 32-bit float as an unsigned integer.
Golang math.Float32frombits Function	Returns the 32-bit float value corresponding to the given IEEE 754 binary representation.
Golang math.Float64bits Function	Returns the IEEE 754 binary representation of a 64-bit float as an unsigned integer.
Golang math.IsInf Function	Checks whether the input is an infinite number.
Golang math.IsNaN Function	Checks whether the input is Not-a-Number (NaN).
Golang math.Nextafter Function	Returns the next representable float value after x towards y.
Golang math.Nextafter32 Function	Returns the next representable float value after x towards y for 32-bit floats.
Golang math.Frexp Function	Breaks the floating-point number into a normalized fraction and an integral power of two.
Golang math.Ldexp Function	Computes the value of x multiplied by 2 raised to the power of exp.

Golang math Package Functions

The math package in Go provides basic constants and mathematical functions such as trigonometric, logarithmic, and exponential functions. Below is a list of commonly used functions in the math package:

Function	Description
Golang math.Abs Function	Returns the absolute value of a given float number.
Golang math.Ceil Function	Returns the smallest integer value greater than or equal to the input.
Golang math.Floor Function	Returns the largest integer value less than or equal to the input.
Golang math.Trunc Function	Returns the integer part of a float number, discarding the fractional part.
Golang math.Mod Function	Returns the floating-point remainder of the division of two numbers.
Golang math.Modf Function	Returns the fractional and integer parts of a floating-point number.
Golang math.Remainder Function	Computes the remainder of the floating-point division of two numbers.
Golang math.Round Function	Rounds the floating-point number to the nearest integer, breaking ties by rounding away from zero.
Golang math.RoundToEven Function	Rounds the floating-point number to the nearest integer, breaking ties by rounding to the even number.
Golang math.Copysign Function	Returns a number with the magnitude of the first argument and the sign of the second.
Golang math.Signbit Function	Checks whether the sign of a floating-point number is negative.
Golang math.Dim Function	Computes the positive difference between two numbers.
Golang math.Min Function	Returns the smaller of two floating-point numbers.
Golang math.FMA Function	Computes the fused multiply-add of three numbers.
Golang math.Exp Function	Returns the exponential value of the input.
Golang math.Exp2 Function	Returns the base-2 exponential value of the input.
Golang math.Expm1 Function	Returns the value of (e^x – 1) of the input.
Golang math.Log Function	Returns the natural logarithm of the input.
Golang math.Log10 Function	Returns the base-10 logarithm of the input.
Golang math.Log1p Function	Returns the natural logarithm of (1 + x) of the input.
Golang math.Log2 Function	Returns the base-2 logarithm of the input.
Golang math.Logb Function	Returns the exponent of the input number.
Golang math.Ilogb Function	Returns the exponent of the input number as an integer.
Golang math.Pow Function	Returns the base raised to the power of the exponent.
Golang math.Pow10 Function	Returns the value of 10 raised to the power of the input.
Golang math.Sqrt Function	Returns the square root of the input.
Golang math.Cbrt Function	Returns the cube root of the input.
Golang math.Sin Function	Returns the sine of the input angle.
Golang math.Cos Function	Returns the cosine of the input angle.
Golang math.Tan Function	Returns the tangent of the input angle.
Golang math.Asin Function	Returns the arcsine of the input.
Golang math.Acos Function	Returns the arccosine of the input.
Golang math.Atan Function	Returns the arctangent of the input.
Golang math.Atan2 Function	Returns the arctangent of y/x considering the sign of both arguments.
Golang math.Hypot Function	Returns the square root of the sum of the squares of two inputs (the hypotenuse).
Golang math.Sincos Function	Computes the sine and cosine of the input angle, returning both.
Golang math.Sinh Function	Returns the hyperbolic sine of the input.
Golang math.Cosh Function	Returns the hyperbolic cosine of the input.
Golang math.Asinh Function	Returns the inverse hyperbolic sine of the input.
Golang math.Acosh Function	Returns the inverse hyperbolic cosine of the input.
Golang math.Atanh Function	Returns the inverse hyperbolic tangent of the input.
Golang math.Gamma Function	Computes the Gamma function of the input.
Golang math.Lgamma Function	Returns the natural logarithm of the absolute value of the Gamma function.
Golang math.Erf Function	Computes the error function of the input.
Golang math.Erfc Function	Computes the complementary error function of the input.
Golang math.Erfinv Function	Computes the inverse of the error function.
Golang math.Erfcinv Function	Computes the inverse of the complementary error function.
Golang math.Float32bits Function	Returns the IEEE 754 binary representation of a 32-bit float as an unsigned integer.
Golang math.Float32frombits Function	Returns the 32-bit float value corresponding to the given IEEE 754 binary representation.
Golang math.Float64bits Function	Returns the IEEE 754 binary representation of a 64-bit float as an unsigned integer.
Golang math.IsInf Function	Checks whether the input is an infinite number.
Golang math.IsNaN Function	Checks whether the input is Not-a-Number (NaN).
Golang math.Nextafter Function	Returns the next representable float value after x towards y.
Golang math.Nextafter32 Function	Returns the next representable float value after x towards y for 32-bit floats.
Golang math.Frexp Function	Breaks the floating-point number into a normalized fraction and an integral power of two.
Golang math.Ldexp Function	Computes the value of x multiplied by 2 raised to the power of exp.

Golang time Package Functions

The time package in Go provides functionality for measuring and displaying time. It includes functions for working with durations, time zones, formatting, and parsing time values. Below is a list of commonly used functions and methods in the time package:

Function/Method	Description
Golang time.After Function	Returns a channel that will receive the current time after at least the specified duration has passed.
Golang time.Sleep Function	Pauses the current goroutine for at least the specified duration.
Golang time.Tick Function	Returns a channel that sends the time with a frequency specified by the duration.
Golang time.ParseDuration Function	Parses a duration string and returns the corresponding duration.
Golang time.Since Function	Returns the time elapsed since the specified time.
Golang time.Until Function	Returns the duration until the specified time.
Golang time.Duration.Abs	Returns the absolute value of the duration.
Golang time.Duration.Hours	Returns the duration as a floating-point number of hours.
Golang time.Duration.Microseconds	Returns the duration as an integer number of microseconds.
Golang time.Duration.Milliseconds	Returns the duration as an integer number of milliseconds.
Golang time.Duration.Minutes	Returns the duration as a floating-point number of minutes.
Golang time.Duration.Seconds	Returns the duration as a floating-point number of seconds.
Golang time.Duration.String	Returns a string representation of the duration.
Golang time.Duration.Truncate	Truncates the duration to a multiple of another duration.
Golang time.FixedZone Function	Returns a fixed time zone with a given name and offset in seconds.
Golang time.LoadLocation Function	Returns the Location with the given name.
Golang time.LoadLocationFromTZData Function	Returns a Location with the given name and timezone data.
Golang time.Location.String	Returns a string representation of the Location.
Golang time.ParseError.Error	Returns the error string of the ParseError.
Golang time.Ticker.Reset	Resets the ticker to adjust its firing interval.
Golang time.Date Function	Returns the Time corresponding to the specified date and time.
Golang time.Now Function	Returns the current local time.
Golang time.Parse Function	Parses a formatted string and returns the corresponding Time.
Golang time.ParseInLocation Function	Parses a formatted string and returns the corresponding Time in the specified Location.
Golang time.Unix Function	Returns the local time corresponding to the given Unix time.
Golang time.UnixMicro Function	Returns the local time corresponding to the given Unix time in microseconds.
Golang time.UnixMilli Function	Returns the local time corresponding to the given Unix time in milliseconds.
Golang time.Time.Add	Adds the specified duration to the time and returns the result.
Golang time.Time.AddDate	Adds the specified number of years, months, and days to the time and returns the result.
Golang time.Time.After	Returns true if the time is after the specified time.
Golang time.Time.AppendFormat	Appends the formatted time to a byte slice and returns the result.
Golang time.Time.Before	Returns true if the time is before the specified time.
Golang time.Time.Clock	Returns the hour, minute, and second of the time.
Golang time.Time.Date	Returns the year, month, and day of the time.
Golang time.Time.Day	Returns the day of the month.
Golang time.Time.Equal	Reports whether the time is equal to the specified time.
Golang time.Time.GoString	Returns a string representation of the time.
Golang time.Time.Hour	Returns the hour within the day of the time.
Golang time.Time.In	Returns the time in the specified location.
Golang time.Time.Local	Returns the time in the local location.
Golang time.Time.Location	Returns the time’s location information.
Golang time.Time.MarshalJSON	Returns the JSON encoding of the time.
Golang time.Time.Minute	Returns the minute within the hour of the time.
Golang time.Time.Month	Returns the month of the time.
Golang time.Time.Nanosecond	Returns the nanosecond within the second of the time.
Golang time.Time.Second	Returns the second within the minute of the time.
Golang time.Time.String	Returns a string representation of the time.
Golang time.Time.Sub	Returns the duration between two times.
Golang time.Time.Truncate	Truncates the time to a multiple of a duration.
Golang time.Time.UTC	Returns the UTC time corresponding to the local time.
Golang time.Time.Weekday	Returns the day of the week specified by the time.
Golang time.Time.Year	Returns the year of the time.
Golang time.Time.Zone	Returns the time zone abbreviation and offset in seconds east of UTC.
Golang time.AfterFunc Function	Waits for the duration to elapse and then calls the provided function.
Golang time.NewTimer Function	Creates a new Timer that will send the current time on its channel after at least the specified duration has passed.
Golang time.Timer.Reset	Resets the timer to its original duration.
Golang time.Timer.Stop	Stops the timer from sending any more events.

Golang bytes Package Functions

The bytes package in Go provides a variety of functions for manipulating byte slices. These functions are useful for searching, modifying, and comparing byte slices. Below is a list of commonly used functions in the bytes package:

Function	Description
Golang bytes.Clone Function	Returns a copy of the given byte slice.
Golang bytes.Compare Function	Compares two byte slices lexicographically.
Golang bytes.Contains Function	Checks whether a byte slice contains another byte slice.
Golang bytes.ContainsAny Function	Reports whether any of the bytes in the second slice are in the first slice.
Golang bytes.ContainsFunc Function	Reports whether any byte in the slice satisfies the provided function.
Golang bytes.ContainsRune Function	Reports whether the byte slice contains the given rune.
Golang bytes.Count Function	Counts the number of non-overlapping instances of a sub-slice in a slice.
Golang bytes.Cut Function	Splits a slice into two around the first instance of a separator.
Golang bytes.CutPrefix Function	Removes the provided prefix from a byte slice.
Golang bytes.CutSuffix Function	Removes the provided suffix from a byte slice.
Golang bytes.Equal Function	Checks if two byte slices are equal.
Golang bytes.EqualFold Function	Performs a case-insensitive comparison of two byte slices.
Golang bytes.Fields Function	Splits the byte slice around each instance of one or more consecutive white space characters.
Golang bytes.FieldsFunc Function	Splits the byte slice around each instance of a byte that satisfies the provided function.
Golang bytes.Split Function	Splits a byte slice into all substrings separated by a separator and returns a slice of the substrings.
Golang bytes.SplitAfter Function	Splits a byte slice after each instance of a separator and returns a slice of the substrings.
Golang bytes.HasPrefix Function	Checks whether the byte slice begins with the specified prefix.
Golang bytes.HasSuffix Function	Checks whether the byte slice ends with the specified suffix.
Golang bytes.Index Function	Finds the first instance of a byte slice in another byte slice.
Golang bytes.IndexAny Function	Finds the first instance of any byte from the second slice in the first slice.
Golang bytes.IndexByte Function	Finds the first instance of the byte in the slice.
Golang bytes.IndexFunc Function	Finds the first byte in the slice that satisfies the provided function.
Golang bytes.LastIndex Function	Finds the last instance of a byte slice in another byte slice.
Golang bytes.LastIndexByte Function	Finds the last instance of the byte in the slice.
Golang bytes.Map Function	Applies a transformation function to each byte in the slice.
Golang bytes.Repeat Function	Returns a new byte slice consisting of the specified number of copies of the original byte slice.
Golang bytes.Replace Function	Returns a copy of the slice with all non-overlapping instances of the old slice replaced by the new slice.
Golang bytes.ReplaceAll Function	Returns a copy of the slice with all instances of the old slice replaced by the new slice.
Golang bytes.Runes Function	Converts the byte slice into a slice of runes (Unicode code points).
Golang bytes.Title Function	Converts the byte slice to title case.
Golang bytes.ToLower Function	Converts all the characters in the byte slice to lowercase.
Golang bytes.ToUpper Function	Converts all the characters in the byte slice to uppercase.
Golang bytes.Trim Function	Trims the leading and trailing bytes contained in the cutset from the slice.
Golang bytes.TrimFunc Function	Trims the leading and trailing bytes that satisfy the provided function.
Golang bytes.TrimLeft Function	Trims the leading bytes contained in the cutset from the slice.
Golang bytes.TrimPrefix Function	Removes the specified prefix from the byte slice.
Golang bytes.TrimRight Function	Trims the trailing bytes contained in the cutset from the slice.
Golang bytes.TrimSpace Function	Trims all leading and trailing white space characters from the byte slice.
Golang bytes.NewBuffer Function	Creates and returns a new buffer using the provided byte slice.
Golang bytes.NewBufferString Function	Creates and returns a new buffer using the provided string.

Golang http Package Functions

The http package in Go is a powerful tool for building web servers and handling HTTP requests and responses. It provides a wide range of functions that help in managing HTTP connections, serving content, and processing requests. Below is a list of commonly used functions in the http package:

Function	Description
Golang http.HandleFunc Function	Registers a function to handle requests for a given pattern.
Golang http.ListenAndServe Function	Starts an HTTP server on a given address and serves incoming requests.
Golang http.ListenAndServeTLS Function	Starts an HTTPS server with TLS on a given address and serves incoming requests.
Golang http.Serve Function	Accepts incoming connections on a listener and serves HTTP requests.
Golang http.ServeTLS Function	Accepts incoming TLS connections on a listener and serves HTTPS requests.
Golang http.ServeFile Function	Serves a file from the server’s file system to the client.
Golang http.ServeContent Function	Serves content from an io.ReadSeeker object, such as a file, to the client.
Golang http.Redirect Function	Redirects the client to a different URL.
Golang http.Error Function	Sends an error response to the client.
Golang http.NotFound Function	Sends a 404 Not Found response to the client.
Golang http.NotFoundHandler Function	Returns a handler that responds with a 404 Not Found.
Golang http.RedirectHandler Function	Returns a handler that redirects the client to a different URL.
Golang http.StripPrefix Function	Returns a handler that serves HTTP requests by removing the given prefix from the request URL’s path.
Golang http.TimeoutHandler Function	Returns a handler that adds a timeout to another handler.
Golang http.MaxBytesReader Function	Wraps an io.ReadCloser to enforce a maximum read limit.
Golang http.NewRequest Function	Creates a new HTTP request with the given method, URL, and optional body.
Golang http.ReadResponse Function	Reads and returns an HTTP response from a buffered reader.
Golang http.NewRequestWithContext Function	Creates a new HTTP request with a context.
Golang http.Get Function	Sends an HTTP GET request to the specified URL.
Golang http.Post Function	Sends an HTTP POST request to the specified URL.
Golang http.PostForm Function	Sends an HTTP POST request with form data.
Golang http.ParseForm	Parses the raw query and updates the provided values.

Golang url Package Functions

The url package in Go is used for parsing and manipulating URLs. It provides functions for URL parsing, encoding, and constructing query parameters, making it essential for web development. Below is a list of commonly used functions in the url package:

Function	Description
Golang url.Parse Function	Parses a URL string and returns a URL structure.
Golang url.QueryEscape Function	Escapes a string so it can be safely placed in a URL query.
Golang url.ParseRequestURI Function	Parses a URL and ensures it is a valid RequestURI.
Golang url.QueryUnescape Function	Unescapes a URL query string.
Golang url.PathEscape Function	Escapes a string for safe inclusion in a URL path segment.
Golang url.PathUnescape Function	Unescapes a URL path string.
Golang url.URL.String	Returns the string representation of a URL.
Golang url.URL.Query	Returns the query parameters of a URL as a Values structure.
Golang url.URL.ResolveReference	Resolves a reference URL against a base URL.
Golang url.URL.Hostname	Returns the hostname of a URL.
Golang url.URL.Port	Returns the port of a URL, if specified.
Golang url.URL.IsAbs	Returns whether the URL is absolute.
Golang url.URL.RequestURI	Returns the request URI of the URL.
Golang url.URL.EscapedPath	Returns the escaped path of the URL.
Golang url.User Function	Returns a Userinfo structure with a username set.
Golang url.UserPassword Function	Returns a Userinfo structure with a username and password set.
Golang url.Values.Encode	Encodes the values into a URL-encoded query string.
Golang url.Values.Get	Gets the first value associated with the given key.
Golang url.Values.Set	Sets the key to the given value, replacing any existing values.
Golang url.Values.Add	Adds the value to the key, appending to any existing values.
Golang url.URL.JoinPath	Joins path elements to the URL’s path.
Golang url.Values.Has	Checks if the key exists in the values.

Golang os Package Functions

The os package in Go provides a platform-independent interface to operating system functionality, including file handling, process management, and environment variables. Here is a list of commonly used functions and methods in the os package:

Function/Method	Description
Golang os.Chdir Function	Changes the current working directory to the specified path.
Golang os.Chmod Function	Changes the mode (permissions) of a file.
Golang os.Chown Function	Changes the owner and group IDs of a file.
Golang os.Chtimes Function	Changes the access and modification times of a file.
Golang os.DirFS Function	Returns a file system rooted at the specified directory.
Golang os.Environ Function	Returns a copy of strings representing the environment variables.
Golang os.Executable Function	Returns the path name for the executable that started the current process.
Golang os.Exit Function	Exits the program with the specified status code.
Golang os.Expand Function	Replaces ${var} or $var in a string based on the mapping function provided.
Golang os.ExpandEnv Function	Replaces ${var} or $var in a string using the environment variables.
Golang os.Getegid Function	Returns the effective group ID of the calling process.
Golang os.Getenv Function	Retrieves the value of the environment variable named by the key.
Golang os.Geteuid Function	Returns the effective user ID of the calling process.
Golang os.Getgid Function	Returns the group ID of the calling process.
Golang os.Getgroups Function	Returns a list of the group IDs of the calling process.
Golang os.Getpagesize Function	Returns the underlying system’s memory page size.
Golang os.Getpid Function	Returns the process ID of the calling process.
Golang os.Getppid Function	Returns the parent process ID of the calling process.
Golang os.Getuid Function	Returns the user ID of the calling process.
Golang os.Getwd Function	Returns a rooted path name corresponding to the current working directory.
Golang os.Hostname Function	Returns the host name reported by the kernel.
Golang os.IsExist Function	Returns true if the error indicates that a file or directory already exists.
Golang os.IsNotExist Function	Returns true if the error indicates that a file or directory does not exist.
Golang os.IsPathSeparator Function	Returns true if the character is a directory separator.
Golang os.IsPermission Function	Returns true if the error indicates a permission problem.
Golang os.IsTimeout Function	Returns true if the error indicates a timeout.
Golang os.LookupEnv Function	Retrieves the value of the environment variable named by the key, and returns whether the key was present.
Golang os.Mkdir Function	Creates a new directory with the specified name and permission bits.
Golang os.MkdirAll Function	Creates a directory named path, along with any necessary parents.
Golang os.MkdirTemp Function	Creates a new temporary directory in the specified directory.
Golang os.Pipe Function	Returns a connected pair of Files; reads from r return bytes written to w.
Golang os.ReadFile Function	Reads the contents of the named file and returns it as a byte slice.
Golang os.Remove Function	Removes the named file or directory.
Golang os.RemoveAll Function	Removes the named file or directory and any children it contains.
Golang os.Rename Function	Renames a file or directory.
Golang os.SameFile Function	Reports whether two files describe the same file system entity.
Golang os.TempDir Function	Returns the default directory to use for temporary files.
Golang os.Truncate Function	Truncates a file to a specified length.
Golang os.Unsetenv Function	Deletes the environment variable named by the key.
Golang os.UserHomeDir Function	Returns the current user’s home directory.
Golang os.WriteFile Function	Writes data to a file named by filename.
Golang os.Create Function	Creates the named file with mode 0666 (before umask) and opens it for writing.
Golang os.CreateTemp Function	Creates a new temporary file in the specified directory, opening it for reading and writing.
Golang os.NewFile Function	Returns a new File for the given file descriptor.
Golang os.Open Function	Opens the named file for reading.
Golang os.OpenFile Function	Opens the named file with the specified flag and perm, if applicable.
Golang os.File.Chdir	Changes the current working directory to the file.
Golang os.File.Chmod	Changes the mode (permissions) of the file.
Golang os.File.Chown	Changes the owner and group IDs of the file.
Golang os.File.Close	Closes the file, rendering it unusable for I/O.
Golang os.File.Fd	Returns the integer Unix file descriptor referencing the open file.
Golang os.File.Name	Returns the name of the file as presented to Open.
Golang os.File.Read	Reads up to len(b) bytes from the file.
Golang os.File.ReadDir	Reads the contents of the directory associated with the file.
Golang os.File.ReadFrom	Reads data from r until EOF and writes it to the file.
Golang os.File.Stat	Returns a FileInfo describing the file.
Golang os.File.Truncate	Truncates the file to a specified length.
Golang os.File.Write	Writes len(b) bytes to the file.
Golang os.File.WriteAt	Writes len(b) bytes to the file starting at byte offset off.
Golang os.File.WriteString	Writes the contents of the string s to the file.
Golang os.Stat Function	Returns a `FileInfo` describing the named file.
Golang os.FindProcess Function	Finds the process with the given process ID, returning a `Process` struct.
Golang os.StartProcess Function	Starts a new process with the given program name and arguments.
Golang os.Process.Kill	Terminates the process by sending the `SIGKILL` signal.

Golang JSON Package Functions

The encoding/json package in Go provides functions for working with JSON data, including marshalling and unmarshalling of data structures. Here is a list of commonly used functions in the json package:

Function	Description
Golang json.Marshal Function	Encodes a Go data structure into JSON format.
Golang json.MarshalIndent Function	Encodes a Go data structure into JSON format with indentation for better readability.
Golang json.Unmarshal Function	Decodes JSON data into a Go data structure.
Golang json.NewDecoder Function	Creates a new JSON decoder that reads from an input stream.
Golang json.NewEncoder Function	Creates a new JSON encoder that writes to an output stream.
Golang json.Compact Function	Removes insignificant space characters from JSON data.
Golang json.Indent Function	Formats JSON data with indentation for better readability.
Golang json.Valid Function	Checks if a byte slice is valid JSON.
Golang json.RawMessage Type	Represents a raw encoded JSON value to delay JSON decoding or precompute a JSON encoding.

Golang Log Package Functions

The log package in Go provides simple logging capabilities, including functions for printing, formatting, and writing log messages. Here is a list of commonly used functions in the log package:

Function	Description
Golang log.Fatal Function	Logs a message and then calls os.Exit(1).
Golang log.Fatalf Function	Formats a message according to a format specifier and logs it, then calls os.Exit(1).
Golang log.Fatalln Function	Logs a message with a newline and then calls os.Exit(1).
Golang log.Panic Function	Logs a message and then calls panic.
Golang log.Panicf Function	Formats a message according to a format specifier and logs it, then calls panic.
Golang log.Panicln Function	Logs a message with a newline and then calls panic.
Golang log.Print Function	Logs a message.
Golang log.Printf Function	Formats a message according to a format specifier and logs it.
Golang log.Println Function	Logs a message with a newline.
Golang log.SetPrefix Function	Sets the prefix for log messages.
Golang log.SetOutput Function	Sets the output destination for log messages.
Golang log.Writer Function	Returns the output destination for log messages.
Golang log.Prefix Function	Returns the prefix for log messages.
Golang log.Output Function	Logs a message to the specified output with a given number of stack frames to skip.

Golang strconv Package Functions

The strconv package in Go provides functions for converting between strings and other data types, such as integers and floating-point numbers. It also includes functions for quoting and unquoting string literals. Below is a list of commonly used functions in the strconv package:

Function	Description
Golang strconv.AppendBool Function	Appends the string form of the boolean to the destination byte slice.
Golang strconv.AppendFloat Function	Appends the string form of the floating-point number to the destination byte slice.
Golang strconv.AppendInt Function	Appends the string form of the integer to the destination byte slice.
Golang strconv.AppendUint Function	Appends the string form of the unsigned integer to the destination byte slice.
Golang strconv.Atoi Function	Converts a string to an integer.
Golang strconv.FormatBool Function	Returns the string representation of a boolean value.
Golang strconv.FormatComplex Function	Returns the string representation of a complex number.
Golang strconv.FormatFloat Function	Returns the string representation of a floating-point number.
Golang strconv.FormatInt Function	Returns the string representation of an integer.
Golang strconv.FormatUint Function	Returns the string representation of an unsigned integer.
Golang strconv.ParseComplex Function	Parses a string as a complex number.
Golang strconv.ParseFloat Function	Parses a string as a floating-point number.
Golang strconv.ParseInt Function	Parses a string as an integer.
Golang strconv.Itoa Function	Converts an integer to its string representation.
Golang strconv.AppendQuote Function	Appends a double-quoted Go string literal representing s to dst and returns the extended buffer.
Golang strconv.AppendQuoteRune Function	Appends a single-quoted Go character literal representing the rune to dst and returns the extended buffer.
Golang strconv.Quote Function	Returns a double-quoted Go string literal representing s.
Golang strconv.QuoteToASCII Function	Returns a double-quoted Go string literal representing s, safely escaped with ASCII only.
Golang strconv.QuotedPrefix Function	Scans the beginning of s for a string literal prefix. The prefix may be single, double, or back quotes.
Golang strconv.UnquoteChar Function	Unquotes a single character, reporting the character’s value and its size.

Golang slices Package Functions

The slices package in Go provides a variety of utility functions to work with slices. These functions include operations such as searching, sorting, comparing, and modifying slices. Below is a list of commonly used functions in the slices package:

Function	Description
Golang slices.BinarySearch Function	Performs a binary search on a sorted slice and returns the position of the target element.
Golang slices.BinarySearchFunc Function	Performs a binary search on a sorted slice using a custom comparison function.
Golang slices.Clip Function	Returns a slice with the same elements as the original, but with a smaller capacity.
Golang slices.Clone Function	Creates a copy of the slice with a new underlying array.
Golang slices.Compact Function	Removes adjacent duplicates from a slice.
Golang slices.CompactFunc Function	Removes adjacent duplicates from a slice using a custom comparison function.
Golang slices.Compare Function	Compares two slices lexicographically.
Golang slices.CompareFunc Function	Compares two slices lexicographically using a custom comparison function.
Golang slices.Concat Function	Concatenates multiple slices into a single slice.
Golang slices.ContainsFunc Function	Checks if any element in the slice satisfies the provided predicate function.
Golang slices.Delete Function	Deletes elements from a slice between specified indices.
Golang slices.DeleteFunc Function	Deletes elements from a slice that satisfy the provided predicate function.
Golang slices.Equal Function	Checks if two slices are equal.
Golang slices.EqualFunc Function	Checks if two slices are equal using a custom comparison function.
Golang slices.Grow Function	Grows the capacity of the slice.
Golang slices.Index Function	Finds the first index of the target element in the slice.
Golang slices.IndexFunc Function	Finds the first index of an element in the slice that satisfies the provided predicate function.
Golang slices.Insert Function	Inserts elements into the slice at the specified index.
Golang slices.IsSorted Function	Checks if the slice is sorted.
Golang slices.IsSortedFunc Function	Checks if the slice is sorted using a custom comparison function.
Golang slices.Max Function	Finds the maximum value in the slice.
Golang slices.MaxFunc Function	Finds the maximum value in the slice using a custom comparison function.
Golang slices.Min Function	Finds the minimum value in the slice.
Golang slices.MinFunc Function	Finds the minimum value in the slice using a custom comparison function.
Golang slices.Replace Function	Replaces elements in a slice between specified indices with elements from another slice.
Golang slices.Reverse Function	Reverses the elements of the slice.
Golang slices.Sort Function	Sorts the elements of the slice.
Golang slices.SortFunc Function	Sorts the elements of the slice using a custom comparison function.
Golang slices.SortStableFunc Function	Sorts the elements of the slice using a custom comparison function, maintaining the order of equal elements.

Golang sort Package Functions

The sort package in Go provides a collection of functions for sorting and searching slices and arrays. These functions cover a variety of data types, including integers, floating-point numbers, and strings. Below is a list of commonly used functions in the sort package:

Function	Description
Golang sort.Find Function	Finds an index of the first occurrence of an element in a sorted slice.
Golang sort.Float64s Function	Sorts a slice of float64s in increasing order.
Golang sort.Float64sAreSorted Function	Reports whether a slice of float64s is sorted in increasing order.
Golang sort.Ints Function	Sorts a slice of ints in increasing order.
Golang sort.IntsAreSorted Function	Reports whether a slice of ints is sorted in increasing order.
Golang sort.IsSorted Function	Reports whether the data is sorted.
Golang sort.Search Function	Searches for the index where a value should be inserted in a sorted slice.
Golang sort.SearchFloat64s Function	Searches for a value in a sorted slice of float64s and returns its index.
Golang sort.SearchInts Function	Searches for a value in a sorted slice of ints and returns its index.
Golang sort.SearchStrings Function	Searches for a value in a sorted slice of strings and returns its index.
Golang sort.Slice Function	Sorts a slice according to a provided comparison function.
Golang sort.SliceIsSorted Function	Reports whether a slice is sorted according to a provided comparison function.
Golang sort.Sort Function	Sorts data according to a provided interface.
Golang sort.Strings Function	Sorts a slice of strings in increasing order.

Golang unicode Package Functions

The unicode package in Go offers a variety of functions to work with Unicode characters, providing tools to test, convert, and classify them. Below is a list of commonly used functions in the unicode package:

Function	Description
Golang unicode.In Function	Checks if a character belongs to one or more ranges of Unicode code points.
Golang unicode.Is Function	Determines if a character belongs to a specific Unicode property.
Golang unicode.IsDigit Function	Reports whether the rune is a decimal digit.
Golang unicode.IsLetter Function	Checks if a character is a letter.
Golang unicode.IsLower Function	Determines if a character is a lowercase letter.
Golang unicode.IsOneOf Function	Checks if a character belongs to one of a set of ranges.
Golang unicode.IsPrint Function	Reports whether the rune is defined as printable.
Golang unicode.IsPunct Function	Reports whether the rune is a Unicode punctuation character.
Golang unicode.IsSpace Function	Checks if a character is a white space.
Golang unicode.IsTitle Function	Determines if a character is a title case letter.
Golang unicode.IsUpper Function	Reports whether the rune is an uppercase letter.
Golang unicode.To Function	Maps the rune to another rune, typically for case conversion.
Golang unicode.ToLower Function	Converts the rune to lowercase.
Golang unicode.ToUpper Function	Converts the rune to uppercase.

Golang regexp Package Functions

The regexp package in Go provides support for regular expressions, enabling pattern matching in strings. Here is a list of commonly used functions in the regexp package:

Function	Description
Golang regexp.Compile Function	Parses a regular expression and returns, if successful, a Regexp object that can be used to match against text.
Golang regexp.CompilePOSIX Function	Compiles a regular expression in POSIX syntax and returns a Regexp object that can be used to match against text.
Golang regexp.MustCompile Function	Compiles a regular expression, panicking if the expression is invalid. It returns a Regexp object that can be used to match against text.
Golang regexp.Match Function	Matches a string against a regular expression pattern and returns a boolean indicating whether it matches.
Golang regexp.MatchReader Function	Matches the text read from an io.Reader against a regular expression pattern and returns a boolean indicating whether it matches.
Golang regexp.MatchReader Function	Matches the text read from an io.Reader against a regular expression pattern and returns a boolean indicating whether it matches.

Golang regexp Package Functions

The regexp package in Go provides support for regular expressions, enabling pattern matching in strings. Here is a list of commonly used functions in the regexp package:

Function	Description
Golang regexp.Compile Function	Parses a regular expression and returns, if successful, a Regexp object that can be used to match against text.
Golang regexp.CompilePOSIX Function	Compiles a regular expression in POSIX syntax and returns a Regexp object that can be used to match against text.
Golang regexp.MustCompile Function	Compiles a regular expression, panicking if the expression is invalid. It returns a Regexp object that can be used to match against text.
Golang regexp.Match Function	Matches a string against a regular expression pattern and returns a boolean indicating whether it matches.
Golang regexp.MatchReader Function	Matches the text read from an io.Reader against a regular expression pattern and returns a boolean indicating whether it matches.
Golang regexp.MatchReader Function	Matches the text read from an io.Reader against a regular expression pattern and returns a boolean indicating whether it matches.

Golang filepath Package Functions

The filepath package in Go provides utilities for manipulating filename paths in a way that is portable between operating systems. Below is a list of commonly used functions in the filepath package:

Function	Description
Golang filepath.Abs Function	Returns an absolute representation of a given path.
Golang filepath.Base Function	Returns the last element of a given path.
Golang filepath.Clean Function	Returns the shortest path name equivalent to the given path by eliminating redundant elements.
Golang filepath.Dir Function	Returns all but the last element of the given path, typically the path’s directory.
Golang filepath.FromSlash Function	Converts forward slashes in a path to the system’s path separator.
Golang filepath.Join Function	Joins any number of path elements into a single path, adding separators as necessary.
Golang filepath.Rel Function	Computes a relative path that is equivalent to the target path when joined to the base path.
Golang filepath.Split Function	Splits a path into a directory and file name component.
Golang filepath.ToSlash Function	Converts the system’s path separator to forward slashes in a given path.
Golang filepath.VolumeName Function	Returns the leading volume name of the given path, such as “C:” for Windows.
Golang filepath.Glob Function	Returns the names of all files matching the given pattern.
Golang filepath.Walk Function	Walks the file tree rooted at the specified directory, calling a function for each file or directory found.
Golang filepath.WalkDir Function	Walks the file tree rooted at the specified directory, similar to Walk, but with an additional context.
Golang filepath.SkipDir Function	Skips the remaining files in the current directory during a walk.
Golang filepath.IsAbs Function	Reports whether the path is absolute.

Golang reflect Package Functions

The reflect package in Go is used for runtime reflection, allowing you to inspect and manipulate objects and types dynamically. Here is a list of commonly used functions in the reflect package:

Function	Description
Golang reflect.TypeOf Function	Returns the reflection Type that represents the dynamic type of the interface.
Golang reflect.ValueOf Function	Returns a new Value initialized to the concrete value stored in the interface.
Golang reflect.Zero Function	Returns a Value representing the zero value for the specified type.
Golang reflect.New Function	Returns a Value representing a pointer to a new zero value for the specified type.
Golang reflect.MakeSlice Function	Creates a new slice value for the specified type, length, and capacity.
Golang reflect.MakeMap Function	Creates a new map value for the specified type.
Golang reflect.MakeChan Function	Creates a new channel value for the specified type and buffer size.
Golang reflect.MakeFunc Function	Creates a new function value with the specified Type that executes the provided function implementation.
Golang reflect.Indirect Function	Returns the value that a pointer or interface value points to.
Golang reflect.DeepEqual Function	Compares two values deeply for equality.
Golang reflect.ArrayOf Function	Returns the Type representing a fixed-size array of the specified length and element type.
Golang reflect.ChanOf Function	Returns the Type representing a channel with the specified direction and element type.
Golang reflect.InterfaceOf Function	Returns the Type representing an interface with the specified methods.
Golang reflect.MapOf Function	Returns the Type representing a map with the specified key and element types.
Golang reflect.PtrTo Function	Returns the Type representing a pointer to the specified type.
Golang reflect.SliceOf Function	Returns the Type representing a slice with the specified element type.
Golang reflect.StructOf Function	Returns the Type representing a struct with the specified fields.