Golang - String to Int conversion

How to convert a String to Int in Golang ?

In golang, converting a String to an Int in Golang is a simple process, but there are a few things to keep in mind. In this blog post, we will walk you through the steps on how to convert a string to an int in Golang, and we will also discuss some of the best practices to follow.

Using the strconv.Atoi() function

One of the most commonly used way to convert a String value to an Integer value in Golang is by using the Atoi() function from the strconv package. The strconv package provides a variety of functions for converting between different data types in Golang.

To use this function, you simply pass the string that you want to convert to an integer as an argument to the function. The function will then return an integer value if the string represents a valid integer, or an error value if the string does not represent a valid integer.

Syntax

int_val, err := strconv.Atoi(string_val)

Example

package main
            
import (
    "fmt"
    "strconv"
)
            
func main() {
    string_val := "123"
    int_val, err := strconv.Atoi(string_val)
    
    if err != nil {
        fmt.Println(err)
        return
    }
    
    fmt.Println(int_val)
}

Output :

123

In the above example we can see that the variable string_val of type String is being passed as an argument to the strconv.Atoi() function which then converts and returns an integer version of it.

Handling Errors

It is important to note that the strconv.Atoi() function can return an error if the string does not represent a valid int.

Example

package main
            
import (
    "fmt"
    "strconv"
)
    
func main() {
    string_val := "bugz"
    int_val, err := strconv.Atoi(string_val)
    
    if err != nil {
        fmt.Println(err)
        return
    }
    
    fmt.Println(int_val)
}

Output :

strconv.ParseInt: parsing "bugz": invalid syntax

In the above example, string "bugz" is being passed to the strconv.Atoi() function.

As "bugz" is not a valid integer it is returning an error.

Using the strconv.ParseInt() function

The strconv.ParseInt() function is more powerful than the strconv.Atoi() function, but it is also more complex. The strconv.ParseInt() function takes a string, a base, and a bit size as input, and returns an int as output, or an error if the string does not represent a valid int

The base parameter specifies the base in which the string is represented. The bit size parameter specifies the number of bits in the integer that is returned.

To use the strconv.ParseInt() function, you simply pass the string that you want to convert to an int to the function as an argument, along with the base and bit size. The function will then return an integer value if the string represents a valid integer, or an error value if the string does not represent a valid integer.

Example

package main

import (
    "fmt"
    "strconv"
)

func main() {
    string_val := "123"
    int_val, err := strconv.ParseInt(string_val, 10, 0)

    if err != nil {
    fmt.Println(err)
    return
    }

    fmt.Println(int_val)
}

Output :

123

In the above example we can see that the variable string_val of type String along with base 10 and bit size 0 is being passed as an argument to the strconv.ParseInt() function which then converts and returns an integer version of the string.

The strconv.ParseInt() function is useful for converting strings to integers in Golang in a variety of situations. For example, you might use the strconv.ParseInt() function to convert a string that represents a hexadecimal number to an integer, or to convert a string that represents a binary number to an integer.

Best Practices

When converting a string to an int in Golang, it is important to follow these best practices:

• Always check the return value of the strconv.Atoi() function to handle errors.

• If you are converting a string that is user-input, validate the input before converting it to an int. This will help to prevent errors and security vulnerabilities.

Conclusion

In conclusion, there are two main ways to convert a string to an int in Golang:

• Using the strconv.Atoi() function: This is the simplest way to convert a string to an int in Golang. It takes a string as input and returns an int as output, or an error if the string does not represent a valid int.

• Using the strconv.ParseInt() function: This function is more powerful than the strconv.Atoi() function, but it is also more complex. It takes a string, a base, and a bit size as input, and returns an int as output, or an error if the string does not represent a valid int.

Which function you should use depends on your specific needs. If you are simply converting a string that represents a decimal number to an integer, then you should use the strconv.Atoi() function. However, if you need to convert a string that represents a number in a different base, or if you need to convert a string that represents a number with a specific bit size, then you should use the strconv.ParseInt() function.