Golang : Proper way to set function argument default value
In PHP, it is easy to specify the default values of a function arguments. All you need to do is just specify $argument_variable = default_value
in the function arguments such as :
function word_limiter($str, $limit = 100, $end_char = '…')
{
...
}
In Golang, it is not permissible to specify default values in a function arguments using the same method in PHP. Attempt to specify default values for the function arguments will cause the source code parser to throw out syntax error
.
This example code below demonstrate the simplest way to set default values in Golang by using the IF statement.
Here you go!
package main
import (
"fmt"
"strconv"
)
func failExample(s string, i int) string {
// wrong way to set default values
// will override input parameters/arguments !!!
s = "empty"
i = -1
return s + strconv.Itoa(i)
}
func okExample(s string, i int) string {
// set default values -- the proper way
if s == "" {
s = "empty"
}
if i == 0 {
i = -1
}
return s + strconv.Itoa(i)
}
func main() {
result := failExample("abc", 123)
fmt.Println("Fail example : ", result)
result1 := okExample("abc", 123)
fmt.Println("Ok example 1 : ", result1)
result2 := okExample("", 123)
fmt.Println("Ok example 2 : ", result2)
result3 := okExample("", 0)
fmt.Println("Ok example 3 : ", result3)
}
Output :
Fail example : empty-1
Ok example 1 : abc123
Ok example 2 : empty123
Ok example 3 : empty-1
References:
https://www.socketloop.com/tutorials/golang-return-multiple-values-from-function
See also : Golang : How to make function callback or pass value from function as parameter?
By Adam Ng
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