Converting a string variable into Boolean, Integer or Float type in Go language

Various types of string conversions are needed while performing tasks in Golang. Package strconv is imported to perform conversions to and from string.

String to Boolean Conversion

ParseBool is used to convert string to boolean value. It accepts 1, t, T, TRUE, true, True as true and 0, f, F, FALSE, false, False as false. Any other value returns an error and will display the value as false.

Example:

// Golang program to convert a string 
// into Boolean data type 

package main 

import ( 
    "fmt"
    "reflect"
    "strconv"
) 

func main() { 

    str := "GeeksforGeeks"

    fmt.Println("Before :", reflect.TypeOf(str)) 
    fmt.Println("String value is: ", str) 
    b, _ := strconv.ParseBool(str) 
    fmt.Println("After :", reflect.TypeOf(b)) 
    fmt.Println("Boolean value is: ", b, "\\n") 

    str1 := "t"

    fmt.Println("Before :", reflect.TypeOf(str1)) 
    fmt.Println("String value is: ", str1) 
    b1, _ := strconv.ParseBool(str1) 
    fmt.Println("After :", reflect.TypeOf(b1)) 
    fmt.Println("Boolean value is: ", b1, "\\n") 

    str2 := "0"

    fmt.Println("Before :", reflect.TypeOf(str2)) 
    fmt.Println("String value is: ", str2) 
    b2, _ := strconv.ParseBool(str2) 
    fmt.Println("After :", reflect.TypeOf(b2)) 
    fmt.Println("Boolean value is: ", b2, "\\n") 

}

---

Output:

Before : string
String value is:  GeeksforGeeks
After : bool
Boolean value is:  false

Before : string
String value is:  t
After : bool
Boolean value is:  true

Before : string
String value is:  0
After : bool
Boolean value is:  false

String to Integer Conversion

ParseInt function is used to convert string to an integer value. It interprets a string in the given base (0, 2 to 36) and bit size (0 to 64) and returns the corresponding value.

Example:

// Golang program to convert String
// into Integer Data type
package main

import (
    "fmt"
    "reflect"
    "strconv"
)

func main() {

    str := "GeeksforGeeks"

    fmt.Println("Before :", reflect.TypeOf(str))
    fmt.Println("String value is: ", str)
    i, _ := strconv.ParseInt(str, 10, 64)
    fmt.Println("After :", reflect.TypeOf(i))
    fmt.Println("Integer value is: ", i, "\\n")

    // parsing the string "100" to int in decimal system (base 10)

    str1 := "100"

    fmt.Println("Before :", reflect.TypeOf(str1))
    fmt.Println("String value is: ", str1)
    i1, _ := strconv.ParseInt(str1, 10, 64) // the base is given as 10 and size for int is 64 bits
    fmt.Println("After :", reflect.TypeOf(i1))
    fmt.Println("Integer value is: ", i1, "\\n")

    // parsing the string "1011" to int in binary system (base 2)
    str2 := "1011"

    fmt.Println("Before :", reflect.TypeOf(str2))
    fmt.Println("String value is: ", str2)
    i2, _ := strconv.ParseInt(str2, 2, 64) // the base is given as 2 and size for int is 64 bits
    fmt.Println("After :", reflect.TypeOf(i2))
    fmt.Println("Integer value is: ", i2, "\\n")
}

---

Output:

Before : string
String value is:  GeeksforGeeks
After : int64
Integer value is:  0 

Before : string
String value is:  100
After : int64
Integer value is:  100 

Before : string
String value is:  1011
After : int64
Integer value is:  11

String to Float Conversion

ParseFloat is used to convert the string to float type with the precision specified by bitSize: 32 for float32, or 64 for float64.

When bitSize=32, the result still has type float64, but it will be convertible to float32 without changing its value.

Example:

// Golang program to convert 
// String into Float Data type 
package main 

import ( 
    "fmt"
    "reflect"
    "strconv"
) 

func main() { 

    str := "3.1415926535"

    fmt.Println("Before :", reflect.TypeOf(str)) 
    fmt.Println("String value is: ", str) 
    f, _ := strconv.ParseFloat(str, 64) // the result will be float64 type
    fmt.Println("After :", reflect.TypeOf(f)) 
    fmt.Println("Float value is: ", f, "\\n") 

    str1 := "3.1415926535"

    fmt.Println("Before :", reflect.TypeOf(str1)) 
    fmt.Println("String value is: ", str1) 
    f1, _ := strconv.ParseFloat(str1, 32) // the result will be still of float64 type
    fmt.Println("After :", reflect.TypeOf(f1)) 
    fmt.Println("Float value is: ", f1, "\\n") 

}

---

Output:

Before : string
String value is:  3.1415926535
After : float64
Float value is:  3.1415926535

Before : string
String value is:  3.1415926535 
After : float64
Float value is:  3.1415927410125732