Regular Expressions 101

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/
((\d*\.\d+)|(?:\d|[1-9]\d+))(?:[f])
/
g
1st Capturing Group
((\d*\.\d+)|(?:\d|[1-9]\d+))
1st Alternative
(\d*\.\d+)
2nd Capturing Group
(\d*\.\d+)
\d
matches a digit (equivalent to [0-9])
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\. matches the character . with index 4610 (2E16 or 568) literally (case sensitive)
\d
matches a digit (equivalent to [0-9])
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
2nd Alternative
(?:\d|[1-9]\d+)
Non-capturing group
(?:\d|[1-9]\d+)
1st Alternative
\d
\d matches a digit (equivalent to [0-9])
2nd Alternative
[1-9]\d+
Match a single character present in the list below
[1-9]
1-9 matches a single character in the range between 1 (index 49) and 9 (index 57) (case sensitive)
\d
matches a digit (equivalent to [0-9])
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
Non-capturing group
(?:[f])
Match a single character present in the list below
[f]
f matches the character f with index 10210 (6616 or 1468) literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
g

Test String

Code Generator

Generated Code

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Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report.
For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php