Regex Tester Online Tool

Regular Expression

Flags(Part 1)

Flags(Part 2)


About Regex Tester Online Tool:

This online Regex Tester tool helps you to test if your regular expression is working correctly. It support Matching Highlight and 6 different Flags, powered by Javascript RegExp.

Flags Type Description
g (global match), find all matches
i ignore case
m multiline; treat beginning and end characters (^ and $) as working over multiple lines
s allows . to match newlines
u Unicode; treat pattern as a sequence of Unicode
y sticky; matches only from the index indicated by the lastIndex

cartoon text editor

Most Common Used Regular Expression:

Email Address: ^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$

Internet URL: [a-zA-z]+://[^\s]*

Chinese Character: [\u4e00-\u9fa5]

Password (starting with a letter, length between 6 and 18, can only contain letters, numbers and underscores): ^[a-zA-Z]\w{5,17}$

Does Regex Tester Online Tool log my data?

Absolutely NOT, this Regex Tester doing all the formatting work on the client side, all logic are implemented by Javascript. There are 2 major advantages: 1.Your data never transmitted in the Open Internet, so you know it's secure; 2.It's much faster than doing all the work in the server side, because there is no Internet Delay.

More information:

Javascript RegExp CheatSheet: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp

Python re Library: https://docs.python.org/3/library/re.html

Wikipedia (Regular Expression): https://en.wikipedia.org/wiki/Regular_expression

Test if string matches a regular expression using Javascript:

var regex_tester = /([A-Z])\w+/g;
var test_string = "This is a Test string."
console.log(regex_tester.test(test_string))

-------------------
> true

Test if string matches a regular expression using Python:

import re

regex_tester = re.compile("([A-Z])\w+", re.I | re.DOTALL)
test_string = "This is a Test string."

if regex_tester.match(test_string):
    print("True")
else:
    print("False")