matching a word to end of string with strpos

Question

Solution: strpos turned out to be the most efficient. Can be done with substr but that creates a temporary substring. Can also be done with regex, but slower than strpos and does not always produce the right answer if the word contains meta-characters (see Ayman Hourieh comment).

Chosen answer:

if(strlen($str) - strlen($key) == strrpos($str,$key))
    print "$str ends in $key"; // prints Oh, hi O ends in O

and best to test for strict equality === (see David answer)

Thanks to all for helping out.

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I'm trying to match a word in a string to see if it occurs at the end of that string. The usual strpos($theString, $theWord); wouldn't do that.

Basically if $theWord = "my word";

$theString = "hello myword";        //match
$theString = "myword hello";        //not match
$theString = "hey myword hello";    //not match

What would be the most efficient way to do it?

P.S. In the title I said strpos, but if a better way exists, that's ok too.

Answer 1

You could use a regular expression.

if(preg_match('/'.$theWord.'$/', $theString)) {
    //matches at the end of the string
}

Or you could use strrpos() and add the length of the word. (strrpos — "Find position of last occurrence of a char in a string") Then see if that is the position of the last character in the string.

Answer 2

You can make use of strrpos function for this:

$str = "Oh, hi O";
$key = "O";

if(strlen($str) - strlen($key) == strrpos($str,$key))
    print "$str ends in $key"; // prints Oh, hi O ends in O

or a regex based solution as:

if(preg_match("#$key$#",$str)) {
 print "$str ends in $key"; // prints Oh, hi O ends in O
}

Answer 3

strpos could be the most efficient in some cases, but you can also substr with a negative value as the second parameter to count backwards from the end of the string:

$theWord = "my word";
$theWordLen = strlen($theWord);

$theString = "hello myword";
$matches = ($theWord ==substr($theString, -1 * $theWordLen);