Regex Tester and Debugger Tool

Free tool which validates the given input string against the given regular expression and matches the output in accordance with the defined Regex.

The tool supports parsing and debugging in Javascript, Python and PHP languages


Regex Parser Flags

Following are the explanations for the flags used.

Regex Parser Flags Description
g (Global) Don't return after the first match
s (Dot All) Dot also matches newline
i (Case Insensitive) Case insensitive match, ignores case of alphabets
m (Multiline) Causes ^ and $ to match the begin/end of each line
D (Dollar) Makes the dollar sign '$', to always match the end of the string, instead of end of the line
x (Extended) Spaces in the pattern are ignored
U (Ungreedy) The match becomes lazy by default

Regex Parser Examples

Following are few example input regex and results for the sample input string

InputRegex Description Input string Result
[A-Z] Character class: Literally matches all characters given inside '[' ']' Once upon A time There was a King with Seven sons
[A-Za-z]+ Checks for one or more matches Once upon A time
([A-Z]) Capturing group: Captures the matches of pattern within '(' and ')' in separate groups Once upon A time
\w Matches any word character (similar to [a-zA-Z0-9_]) Site
([A-Z])\w+ Capture all groups starting with uppercase alphabet and match all words starting with upper case alphabet followed by word character Once

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