CODEWITHSUNDEEP
php
tester
tester

Reputation: 23189

If no arguments are provided in the function, how do I test to see if it is left blank?

<?php    
/* Copyright Date
--------------------------*/
function copyright_date($creation_year) {
    $current_year = date('Y');

    if ($creation_year == $current_year || $creation_year == '') {
        echo $current_year;
    } 
    else {
        echo $creation_year . '-' . $current_year;
    }           
}
?>

If someone forgets to add the argument (the year the website was created), e.g.

<?php copyright_date(); ?>

instead of:

<?php copyright_date(2009); ?>

how would I test to see if the argument was left blank? In my if statement, that's what $creation_year == '' is for, but since the argument isn't a string, it doesn't work.

Upvotes: 1

Views: 2950

Answers (4)

ttvd94
ttvd94

Reputation: 330

Actually I think you MUST use func_num_args(). It's much more safer in practice.

function copyright_date($creation_year = NULL) {
    if(!func_num_args()) {
        // Nothing passed to the function
    }
}

why? Because if you set a default value, let's say function copyright_date($creation_year = NULL) you wouldn't know if NULL is passed. Also isset() returns true if you set a default value.

Upvotes: 2

user2728488
user2728488

Reputation: 25

If anyone needs additional clarification on the answer:

You can try to set a function's parameters to NULL. This will set the value of the variable (in your case $creation_year) to an empty variable. The variable has been declared, but contains no value. When the function is called like so: 

<?php copyright_date();  ?>

Your function will execute the code in the else block.

If the function is called the other way (with argument supplied), like so: 

 <?php copyright_date($creation_year);  ?>

The argument supplied replaces the the NULL value, and the code in the If block is run.

Considering this, you also need to have this : 

|| $creation_year == NULL

In your if condition. This will check if the value of $creation_year is empty.

Upvotes: 0

Paige Ruten
Paige Ruten

Reputation: 176753

Make $creation_year an optional argument with a default value of NULL.

function copyright_date($creation_year=NULL) {

Now inside the function just test if $creation_year is equal to NULL, which will happen when the function is called with no arguments.

Upvotes: 4

Christian C. Salvad&#243;
Christian C. Salvad&#243;

Reputation: 827832

You could use the isset function

if ($creation_year == $current_year || !isset($creation_year)){
 //...
}

Upvotes: 0

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