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Regular Expression
Test String
Substitution
Replace the code without content loss
If you need to replace code with variable content mixed in, this will assist in the replacing process.Comments
Top Regular Expressions
Match string not containing string
Check if a string only contains numbers
Match elements of a url
Match an email address
Validate an ip address
Match or Validate phone number
Match html tag
Match dates (M/D/YY, M/D/YYY, MM/DD/YY, MM/DD/YYYY)
Empty String
Checks the length of number and not starts with 0
Match a valid hostname
Not Allowing Special Characters
Validate datetime
string between quotes + nested quotes
Match brackets
Url
match a wide range of international phone number
Match IPv6 Address
email validation
RegEx Allowing Number Only
Check if a string only contains numbers
Match elements of a url
Match an email address
Validate an ip address
Match or Validate phone number
Match html tag
Match dates (M/D/YY, M/D/YYY, MM/DD/YY, MM/DD/YYYY)
Empty String
Checks the length of number and not starts with 0
Match a valid hostname
Not Allowing Special Characters
Validate datetime
string between quotes + nested quotes
Match brackets
Url
match a wide range of international phone number
Match IPv6 Address
email validation
RegEx Allowing Number Only
Cheat Sheet
| Character classes | |
|---|---|
| . | any character except newline |
| \w \d \s | word, digit, whitespace |
| \W \D \S | not word, digit, whitespace |
| [abc] | any of a, b, or c |
| [^abc] | not a, b, or c |
| [a-g] | character between a & g |
| Anchors | |
| ^abc$ | start / end of the string |
| \b | word boundary |
| Escaped characters | |
| \. \* \\ | escaped special characters |
| \t \n \r | tab, linefeed, carriage return |
| \u00A9 | unicode escaped © |
| Groups & Lookaround | |
| (abc) | capture group |
| \1 | backreference to group #1 |
| (?:abc) | non-capturing group |
| (?=abc) | positive lookahead |
| (?!abc) | negative lookahead |
| Quantifiers & Alternation | |
| a* a+ a? | 0 or more, 1 or more, 0 or 1 |
| a{5} a{2,} | exactly five, two or more |
| a{1,3} | between one & three |
| a+? a{2,}? | match as few as possible |
| ab|cd | match ab or cd |
