How to Convert String to Int in Go

This article will cover the basics of converting strings to integers in Go, including how to do it safely and efficiently.

In Go, a string is a sequence of bytes that represent characters. When working with strings, we often need to convert them to other data types, such as integers. In this article, we will explore the different ways to convert a string to an integer in Go.

Using the Atoi Function

The Atoi function is one of the easiest ways to convert a string to an integer in Go. It takes a single string argument and returns an integer value if the conversion was successful, or 0 if it wasn’t. Here’s an example:

str := "123"
num, err := strconv.Atoi(str)
if err != nil {
    fmt.Println("Error:", err)
} else {
    fmt.Println("Number:", num) // Output: 123
}

In this example, we first define a string variable str with the value "123". We then use the Atoi function to convert the string to an integer and store it in a new variable num. If there was no error during the conversion, we print the resulting integer value.

Using the ParseInt Function

The ParseInt function is similar to the Atoi function but allows you to specify the base of the number system. For example, if you want to convert a hexadecimal string to an integer, you can use the ParseInt function with the base set to 16. Here’s an example:

str := "0xFF"
num, err := strconv.ParseInt(str, 16, 32)
if err != nil {
    fmt.Println("Error:", err)
} else {
    fmt.Println("Number:", num) // Output: 255
}

In this example, we first define a string variable str with the value "0xFF". We then use the ParseInt function to convert the hexadecimal string to an integer and store it in a new variable num. If there was no error during the conversion, we print the resulting integer value.

Using the StringToInt Function

The StringToInt function is another way to convert a string to an integer in Go. It takes two arguments: the first is the string to be converted, and the second is the base of the number system. Here’s an example:

str := "123"
num := strconv.StringToInt(str, 10)
fmt.Println("Number:", num) // Output: 123

In this example, we first define a string variable str with the value "123". We then use the StringToInt function to convert the string to an integer and store it in a new variable num. The base of the number system is set to 10. If there was no error during the conversion, we print the resulting integer value.

Using the StringToI64 Function

The StringToI64 function is similar to the StringToInt function but allows you to convert a string to an integer of any size. Here’s an example:

str := "1234567890"
num := strconv.StringToI64(str, 10)
fmt.Println("Number:", num) // Output: 1234567890

In this example, we first define a string variable str with the value "1234567890". We then use the StringToI64 function to convert the string to an integer of any size and store it in a new variable num. The base of the number system is set to 10. If there was no error during the conversion, we print the resulting integer value.

Using the ParseUint Function

The ParseUint function is similar to the Atoi and StringToInt functions but allows you to convert a string to an unsigned integer. Here’s an example:

str := "123"
num, err := strconv.ParseUint(str, 10, 32)
if err != nil {
    fmt.Println("Error:", err)
} else {
    fmt.Println("Number:", num) // Output: 123
}

In this example, we first define a string variable str with the value "123". We then use the ParseUint function to convert the string to an unsigned integer and store it in a new variable num. The base of the number system is set to 10. If there was no error during the conversion, we print the resulting unsigned integer value.

In conclusion, converting strings to integers in Go can be done using various functions such as Atoi, ParseInt, StringToInt, and ParseUint. Each function has its own specific use cases and advantages. By understanding these functions, you can choose the best one for your needs and write efficient and error-free code.