PHP === vs !===

Question

When it comes to this function, everything seems to work alright

function found($in,$find){
    if(strpos($in,$find) !== false)
        return true;
    else
        return false;
}

if(found("Sample text","text"))
    echo 'Found 1';
if(found("Sample text","house"))
    echo 'Found 2';

Result:

Found 1

But, if I use === I just do not get the right results:

function found($in,$find){
    if(strpos($in,$find) === true)
        return true;
    else
        return false;
}

if(found("Sample text","text"))
    echo 'Found 1';
else
    echo 'Not found';
if(found("Sample text","house"))
    echo 'Found 2';
else
    echo 'Not found';

Result:

Not foundNot found

Both return false

Why is that?

`strpos()` returns `false` if not found and the position if found so it will never `=== true` but it will `== true` if the position is not 0. — AbraCadaver, May 12 '14 at 21:50
Because the strpos() function returns either a Boolean false, or an integer >= 0.... a Boolean true is never returned under any circumstance — Mark Baker, May 12 '14 at 21:50

score 4 · Accepted Answer · answered May 12 '14 at 21:50

4

function strpos() never returns true.

It returns integer being the index of the first occurance of the needle, and if the needle doesn't occur it returns boolean false.

answered May 12 '14 at 21:50

nl-x

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score 4 · Answer 2 · edited May 12 '14 at 22:01

4

=== checks the type as well, strpos returns an integer (except it returns false if the needle was not found) and you are comparing it to boolean true.

edited May 12 '14 at 22:01

halfer

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answered May 12 '14 at 21:50

ka_lin

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not true. strpos returns INT and boolean. (Just not boolean true) – nl-x May 12 '14 at 21:52

PHP === vs !===

2 Answers2