What's the best way to achieve the following:
I have a $img variable containing e.g. myimage_left.jgp, someimage_center.jpg or img_right.jpg
What's the best way to test for _left, _right or _center of the filename and extract this value and store it in a variable?
So I have $img which already contains the complete basename of the file. And I need to have $pos which should hold _center or _left or _right.
What's the way to do that? preg_match, strpos, etc?
A regex would be simplest:
$input = 'foo_left.jpg';
if(!preg_match('/_(left|right|center)/', $input, $matches)) {
// no match
}
$pos = $matches[0]; // "_left", "_right" or "_center"
Update:
For a more defensive-minded approach (if there might be multiple instances of "_left" and
friends in the filename), you can consider adding to the regex.
This will match only if the l/r/c is followed by a dot:
preg_match('/(_(left|right|center))\./', $input, $matches);
This will match only if the l/r/c is followed by the last dot in the filename (which practically means that the base name ends with the l/r/c specification):
preg_match('/(_(left|right|center))\\.[^\\.]*$/', $input, $matches);
And so on.
If using these regexes, you will find the result in $matches[1] instead of $matches[0].
_left.jpg.I can have many 'extensions' if I want to.png_center.png.
[^.]. Furthermore I would use a + there instead of an * in order to ensure that there is some file extension.
$matches[0] will contain the full string. You want $matches[1] which'll have the first capture group in it.Someone will probably have more elegant solution but I would use strpos like you suggest.
if (strpos(strtoupper($img), '_LEFT') > 0) $pos = '_LEFT'
you could then expand it to
$needleArray = arra('_LEFT', '_CENTER', '_RIGHT');
foreach ($needleArray as $needle) {
if (strpos(strtoupper($img), $needle) > 0) $pos = $needle
}
This is assuming you can't have more than one value for pos.
Non-regex option
$img = 'myimage_left.jpg';
$find = array( 'left', 'center', 'right' );
if ( in_array( $pos = end( explode( '_', basename( $img, '.jpg' ) ) ), $find ) ) {
echo $pos;
}
If you want to avoid regexes, you could just do
$underScores = explode("_", $img);
$endOfFileName = end($underScores);
$withoutExtensionArr = explode(".", $img);
$leftRightOrCenter = $withoutExtensionArr[0];
Then check the contents of left right or center
