array_search Boolean return values

Question

I have been struggling with array_search for a bit and although I think I understand it now, I just want to make absolutely sure I understand the logic behind the way my code is executing.

I am trying to write a function that will add an element to an array if it is not in the array to begin with, and remove it if it is. Simple, right?

$k = array_search($needle, $haystack)
if ( $k === FALSE ) {
    $haystack[] = $needle;
} else {
    unset($haystack[$k]);
}

Is this the most efficient way to write this? It seems like there should be a way to assign the value of $k and at the same time check whether its value is FALSE or anything else (including 0)?

Looks good apart from the missing ; on first line

Hanky Panky
– Hanky Panky

2013-03-29 16:16:47 +00:00
Commented Mar 29, 2013 at 16:16 — Hanky Panky
– Hanky Panky, Commented Mar 29, 2013 at 16:16

Jocelyn · Accepted Answer · 2013-03-29 16:32:28Z

3

You can shorten your code this way:

if (($k = array_search($needle, $haystack)) === FALSE) {
    $haystack[] = $needle;
} else {
    unset($haystack[$k]);
}

The first line of code performs the search, stores the returned value in $k, and checks if this value is exactly equal to FALSE or not.

Documentation: array_search

edited Mar 29, 2013 at 16:32

answered Mar 29, 2013 at 16:15

Jocelyn

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2 Comments

Jocelyn Over a year ago

@cpattersonv1 $k is always set. Either with false if $needle is not found, or with a key value to indicate where to find $needle in $haystack array. Check the manual page for array_search for more information.

Jocelyn Over a year ago

@cpattersonv1 The parentheses are there for a good reason. I don't see why you would want to remove them.

Vivek Sadh · Accepted Answer · 2013-03-29 16:27:49Z

0

Your code is fine but you can do it this way:-

if (($k = array_search($needle, $haystack)) == FALSE) 
{
$haystack[] = $needle;
} 
else 
{
unset($haystack[$k]);
}

answered Mar 29, 2013 at 16:27

Vivek Sadh

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1 Comment

caseyy Over a year ago

No he's missing the triple equals sign. This won't work if the matched element has a key of 0.

AbsoluteƵERØ · Accepted Answer · 2013-03-29 16:59:35Z

0

Outside of wrapping it with a function so you can reuse it, what you have works well. Most of the other examples are just rewriting what you've written already.

<?php
$haystack = array(
'5','6','7',
);

$needles = array('3','4','2','7');
print_r($haystack);


function checker($needle,$haystack){
    $k = array_search($needle, $haystack);
    if ( $k === FALSE ) {
        $haystack[] = $needle;
    } else {
        unset($haystack[$k]);
    }
    return $haystack;
}


foreach($needles as $value){
    $haystack = checker($value,$haystack);
    print_r($haystack);

}



?>

answered Mar 29, 2013 at 16:59

AbsoluteƵERØ

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