Find character before or after of string using preg_grep() in PHP

问题

I need to find any character before or after of a word using PHP preg_grep() from array. I have a array like following

$findgroup = array("aphp", "phpb", "dephpfs", "potatoes");

I need to find the values from the array which have 'php' word with a single or double character before or after(either side, not both side) the word 'php'. The result should be 'aphp','phpb' word from the array.

I tried with the following code but not works.

$result[] = preg_grep("/(.{1})php(.{1})/", $findgroup);

回答1:

Anchor your regex and add quantifier for character before and after:

$findgroup = array("aphp", "phpb", "dephpfs", "potatoes", "aphpb", "php");
$result = preg_grep("/^(?:.{1,2}php|php.{1,2})$/", $findgroup);       
print_r($result);

Output:

Array
(
    [0] => aphp
    [1] => phpb
)

来源：https://stackoverflow.com/questions/43868798/find-character-before-or-after-of-string-using-preg-grep-in-php