For those of you who use Preg_Replace. Preg_replace is a function that uses regular expressions to search and replace a string.
Why?
Because my understanding with regular expressions is shady and varies from language to language, I've written this article as a quick reference point.
How?
Well you use this in your PHP scripts, the examples below are meant to help but feel free to comment if they do not:
Surround string (apostrophes) with red styling
Convert: this='a string' » this='a string'
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$string_formatted = preg_replace ( '/\'([^\']+)\'/', '<span style="color:red">$0</span>', $string_original );
- $string_formatted = preg_replace ( '/\'([^\']+)\'/', '<span style="color:red">$0</span>', $string_original );
Surround string (apostrophes) with red styling but ignore escaped apostrophes:
Convert: this='joe\'s string' » this='joe\'s string'
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$string_formatted = str_replace('\\\'', '\\\'', $string_formatted); // bit of a copout I know
$string_formatted = preg_replace ( '/\'([^\']+)\'/', '<span style="color:red">$0</span>', $string_formatted );
- $string_formatted = str_replace('\\\'', '\\\'', $string_formatted); // bit of a copout I know
- $string_formatted = preg_replace ( '/\'([^\']+)\'/', '<span style="color:red">$0</span>', $string_formatted );
Surround string (apostrophes) with red styling and evaluate:
Convert: this='some <html> string' » this='some string'
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$string_formatted = preg_replace ( '/\'([^\']+)\'/e', 'stripslashes(strip_tags("$0"))', $string_formatted ); // really important to suffix the expression with 'e'
$string_formatted = preg_replace ( '/\'([^\']+)\'/', '<span style="color:red">$0</span>', $string_formatted );
- $string_formatted = preg_replace ( '/\'([^\']+)\'/e', 'stripslashes(strip_tags("$0"))', $string_formatted ); // really important to suffix the expression with 'e'
- $string_formatted = preg_replace ( '/\'([^\']+)\'/', '<span style="color:red">$0</span>', $string_formatted );
Surround string (backticks) with darkred styling
Convert: `mysql_reserved_word`=my_alias » `mysql_reserved_word`=my_alias
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$string_formatted = preg_replace('/<pre>(.*)<\/pre>/eis', "'<span style="color:red">'.'$1'.'</span>'", $string_original);
- $string_formatted = preg_replace('/<pre>(.*)<\/pre>/eis', "'<span style="color:red">'.'$1'.'</span>'", $string_original);
Replace contents between two tags (<pre></pre>)
Convert: my outside string <pre>is now inside</pre> » my outside string is now inside
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$string_formatted = preg_replace('/(<pre>)(.*)(<\/pre>)/eis', "'<span style="color:red">' . '$1' . '$2' . '$3' . '</span>'", $string_original);
- $string_formatted = preg_replace('/(<pre>)(.*)(<\/pre>)/eis', "'<span style="color:red">' . '$1' . '$2' . '$3' . '</span>'", $string_original);
Replace contents between two tags (<pre></pre>) INCLUSIVE
Convert: my outside string <pre>is now inside</pre> » my outside string <pre>is now inside</pre>
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$startPoint = '<!-- MY START STRING -->';
$endPoint = '<!-- MY END STRING -->';
$string_formatted = preg_replace('#('.preg_quote($startPoint).')(.*)('.preg_quote($endPoint).')#si', '$0', $string_original);
- $startPoint = '<!-- MY START STRING -->';
- $endPoint = '<!-- MY END STRING -->';
- $string_formatted = preg_replace('#('.preg_quote($startPoint).')(.*)('.preg_quote($endPoint).')#si', '$0', $string_original);
Replace contents between two strings
Convert: <!-- MY START STRING -->Hello World!<!-- MY END STRING --> » Hello World!
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$string_formatted = preg_replace( '/@[a-z]+/i','<span style="color:red;">$0</span>', $string_original);
-- METHOD #2: equivalent using preg_match_all
$matches = null;
preg_match_all('/(?!\b)(@\w+\b)/',$string_original,$matches);
foreach ($matches as $match) {
foreach ($match as $mystring) {
$string_formatted = str_replace( $mystring, '<span style="color:red;">'.$mystring.'</span>', $string_formatted);
}
}
- $string_formatted = preg_replace( '/@[a-z]+/i','<span style="color:red;">$0</span>', $string_original);
- -- METHOD #2: equivalent using preg_match_all
- $matches = null;
- preg_match_all('/(?!\b)(@\w+\b)/',$string_original,$matches);
- foreach ($matches as $match) {
- foreach ($match as $mystring) {
- $string_formatted = str_replace( $mystring, '<span style="color:red;">'.$mystring.'</span>', $string_formatted);
- }
- }
Replace all @words
Convert: Hello @World » Hello @World
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$string_formatted = preg_replace( '/\$[a-z_]+/i','<span style="color:red;">$0</span>', $string_original);
- $string_formatted = preg_replace( '/\$[a-z_]+/i','<span style="color:red;">$0</span>', $string_original);
Replace all $wordpart1_wordpart2 (allow underscores)
Convert: Hello $New_World » Hello $New_World
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$string_formatted = preg_replace( '/[a-z]+\(/i','<span style="color:red;">$0</span>', $string_original);
- $string_formatted = preg_replace( '/[a-z]+\(/i','<span style="color:red;">$0</span>', $string_original);
Replace all words with suffixed character
Convert: Hello( World ) » Hello( World )
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$string_formatted = preg_replace( '/[a-z_ -]+\ \(/i','<span style="color:red;">$0</span>', $string_original);
- $string_formatted = preg_replace( '/[a-z_ -]+\ \(/i','<span style="color:red;">$0</span>', $string_original);
Replace all words with suffixed character and html entity
Convert: Hello ( World ) » Hello ( World )
$string_formatted = preg_replace( '/[a-z_ -]+\ \(/i','<span style="color:red;">$0</span>', $string_original);
Anymore? Please leave a comment if I've missed some useful ones out.
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