Parser in PHP using regular expressions

You can use regular expressions in PHP by using the function preg_match ( string $pattern , string $subject [, array &$matches [, int $flags = 0 [, int $offset = 0 ]]] ) . Only the first two paremeters are mandatory and they are the regex and the string where you want to search respectively.

In case of finding a result, preg_match() returns an array where the item at index 0 is the whole match. From 1 onwards they are placed the different groups of your regular expressions (in case there is any). If no match is found, preg_match() returns null.

One of the details that must be taken into account when using regular expressions on PHP is that they must be enclosed by forward slashes (/), e.g. $multiline_meaning_re = '/^([A-za-z ,"().\';:]+)/'; . This regular expression matches any string with any set of letters, spaces, commas, double and single quotes, parenthesis points, colon and/or semicolon.

As a complete example, the following snippet opens a file, parses it to look for English idioms and uploads all of them a MySQL database.

You can find further information about the preg_match() in the PHP official documentation.

Rubén Sánchez Mínguez
IC design engineer en Analog Devices

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