PHP function parameters my_func($param='')

Question

I saw some PHP today I don't understand, can anyone explain it to me?

function my_func($param='')
{

    if (empty($param))
    {
        return false;
    }
    else
    {
        return true;
    }
}

What I don't understand is the $param variable being assigned an empty string but somehow not being empty inside the function? Is this just a default value?

possible duplicate of PHP function with unlimited number of parameters — Shiplu Mokaddim
– Shiplu Mokaddim, Commented Mar 6, 2012 at 14:30
@Shiplu I disagree. That question is a bit different, and it makes no reference to default argument values. — Wiseguy
– Wiseguy, Commented Mar 6, 2012 at 14:34

MakuraYami · Accepted Answer · 2012-03-06 14:35:21Z

2

my_func("string") //makes $param "string"

my_func() //picks default making $param ''

You can have required and optional params like

function my_func($param1, $param2='default')

You can NOT put optional params behind required params

function my_func($param1='', $param2) //gives errors.

answered Mar 6, 2012 at 14:35

MakuraYami

3,4283 gold badges18 silver badges19 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Hans Wassink · Accepted Answer · 2012-03-06 14:25:13Z

1

Yes, you can assign a default value to a param in PHP. You can overwrite it using my_func("None Empty String") for example!

answered Mar 6, 2012 at 14:25

Hans Wassink

2,5973 gold badges33 silver badges46 bronze badges

Comments

George Cummins · Accepted Answer · 2012-03-06 14:25:39Z

1

Your assumption was correct; this allows the developer to assign a default value to the parameter.

If the calling code does not pass a parameter value, the function returns false. Otherwise, $param is non-empty, and the function returns true.

A potential pitfall with this code is the case of a parameter being passed with an empty value (0, null, etc). The code will return false even though a parameter was passed.

answered Mar 6, 2012 at 14:25

George Cummins

29k8 gold badges74 silver badges91 bronze badges

Comments

Ryan Kempt · Accepted Answer · 2012-03-06 14:26:44Z

1

Yes, the variable inside the parenthesis of the function declaration is a default value, and is used so you can call the function like this:

echo my_func();

Without needing to actually pass a variable to the function at all.

answered Mar 6, 2012 at 14:26

Ryan Kempt

4,2096 gold badges32 silver badges41 bronze badges

Collectives™ on Stack Overflow

PHP function parameters my_func($param='')

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related