How to Convert string to integer type in Golang?

Strings in Golang is a sequence of variable-width characters where each and every character is represented by one or more bytes using UTF-8 Encoding. In Go language, both signed and unsigned integers are available in four different sizes. In order to convert string to integer type in Golang, you can use the following methods.

1. Atoi() Function: The Atoi stands for ASCII to integer and returns the result of ParseInt(s, 10, 0) converted to type int.

Syntax:

func Atoi(s string) (int, error)

Example:

Go

// Go program to illustrate how to
// Convert string to the integer type

package main

import (
    "fmt"
    "strconv"
)

func main() {

    str1 := "123"

    // using ParseInt method
    int1, err := strconv.ParseInt(str1, 6, 12)

    fmt.Println(int1)

    // If the input string contains the integer
    // greater than base, get the zero value in return
    str2 := "123"

    int2, err := strconv.ParseInt(str2, 2, 32)
    fmt.Println(int2, err)

}

Output:

123
0 strconv.Atoi: parsing "12.3": invalid syntax

2. ParseInt() Function: The ParseInt interprets a string s in the given base (0, 2 to 36) and bit size (0 to 64) and returns the corresponding value i.

Syntax:

func ParseInt(s string, base int, bitSize int) (i int64, err error)

Example:

Go

// Go program to illustrate how to
// Convert string to the integer type

package main

import (
    "fmt"
    "strconv"
)

func main() {

    str1 := "123"

    // using ParseInt method
    int1, err := strconv.ParseInt(str1, 6, 12)

    fmt.Println(int1)

    // If the input string contains the integer
    // greater than base, get the zero value in return
    str2 := "123"

    int2, err := strconv.ParseInt(str2, 2, 32)
    fmt.Println(int2, err)

}

Output:

51
0 strconv.ParseInt: parsing "123": invalid syntax