When working with regular expressions, capturing spaces can be crucial. For instance, let's say you want to ensure a string allows letters, numbers, and spaces only.
To match a single space in PHP, use the following regex:
" "
For multiple spaces, use:
" *" (two spaces and an asterisk) " +" (one space and a plus)
These patterns apply to most regex engines:
For modern regex engines, consider using "s" and its variations.
To remove invalid characters, including spaces:
$newtag = preg_replace ("/[^a-zA-Z0-9 ]/", "", $tag);
To ensure proper spacing between words:
$newtag = preg_replace ("/ +/", " ", $tag); $newtag = preg_replace ("/^ /", "", $tag); $newtag = preg_replace ("/ $/", "", $tag);
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