How to convert a boolean string type value to a bool type value in Go or Golang?

Published August 22, 2022

To convert a boolean-based string type value to a bool type value, you can use the ParseBool() method from the strconv standard package in Go or Golang.

The ParseBool() method:

  • accepts a string type value as its argument
  • and returns 2 values, the first one being the converted bool type value if any and the second being the error data if any.

TL;DR

package main

// import `strconv` package
import (
    "fmt"
    "strconv"
)

func main() {
    // convert `string` type value of "true"
    // using the `ParseBool()` method by passing
    // the value "true" as its argument
    convertedBoolVal, err := strconv.ParseBool("true")
    // check if any error happened
    if err != nil {
        fmt.Println(err.Error())
        return
    }

    // log output of the `convertedBoolVal`
    // variable to the console
    fmt.Println(convertedBoolVal) // true and the type is bool ✅
}

For example, let's say we need to convert a boolean string type value of "true" to its corresponding bool type value.

To do that let's first import the strconv standard package like this,

package main

// import `strconv` package
import "strconv"

After importing the package, inside the main() function we can use the ParseBool() method from the strconv package and pass the string type value of "true" as its argument to the function.

It can be done like this,

package main

// import `strconv` package
import "strconv"

func main(){
    // convert `string` type value of "true"
    // using the `ParseBool()` method by passing
    // the value "true" as its argument
    strconv.ParseBool("true")
}

The ParseBool() method returns 2 values where the first value is the converted bool type value if successfully converted and the second value is the error data if anything happened during the conversion. To capture these 2 data, let's assign 2 variables.

It can be done like this,

package main

// import `strconv` package
import "strconv"

func main(){
    // convert `string` type value of "true"
    // using the `ParseBool()` method by passing
    // the value "true" as its argument
    convertedBoolVal, err := strconv.ParseBool("true")
}

Before dealing with the converted bool value we need to check if there was any error during the conversion process. Let's use a simple if conditional statement and check to see if the err data variable is nil or not. If it is not nil, then there must have been an error that happened during the conversion.

It can be done like this,

package main

// import `strconv` package
import (
    "fmt"
    "strconv"
)

func main(){
    // convert `string` type value of "true"
    // using the `ParseBool()` method by passing
    // the value "true" as its argument
    convertedBoolVal, err := strconv.ParseBool("true")
    // check if any error happened
    if err != nil {
        fmt.Println(err.Error())
        return
    }
}

If there is no error then it is safe to assume that the convertedBoolVal variable must be having the converted bool type value. Let's log the output to the console like this,

package main

// import `strconv` package
import (
    "fmt"
    "strconv"
)

func main() {
    // convert `string` type value of "true"
    // using the `ParseBool()` method by passing
    // the value "true" as its argument
    convertedBoolVal, err := strconv.ParseBool("true")
    // check if any error happened
    if err != nil {
        fmt.Println(err.Error())
        return
    }

    // log output of the `convertedBoolVal`
    // variable to the console
    fmt.Println(convertedBoolVal) // true and the type is bool ✅
}

As you can see that the string type value of "true" is successfully converted to its corresponding bool type value which is what we want.

See the above code live in The Go Playground.

Now let's try to give a string type value composed of alphabets like John Doe and then try to convert it to its bool type value like this,

package main

// import `strconv` package
import (
    "fmt"
    "strconv"
)

func main() {
    // convert `string` type value of "John Doe"
    // using the `ParseBool()` method by passing
    // the value "John Doe" as its argument
    convertedBoolVal, err := strconv.ParseBool("John Doe") // Error ❌. strconv.ParseBool: parsing "John Doe": invalid syntax
    // check if any error happened
    if err != nil {
        fmt.Println(err.Error())
        return
    }

    // log output of the `convertedBoolVal`
    // variable to the console
    fmt.Println(convertedBoolVal)
}

As you can see that the Go compiler shows us an error saying that strconv.ParseBool: parsing "John Doe": invalid syntax which essentially means that it cannot parse this value to its corresponding bool type value.

See the above code live in The Go Playground.

That's all 😃!

Feel free to share if you found this useful 😃.


Share on: Facebook Twitter