CODEWITHSUNDEEP
javascriptregex
Leroy Bakker
Leroy Bakker

Reputation: 11

Regular expression issue in javascript

Im trying to get all the power calculations out of a string using reg exp's i tried the following code:

var regex = new RegExp('[0-9]+[^]{1}[0-9]+');
regex.exec('1^2');

this works and returns 1^2 but when i try to use the following string:

regex.exec('1+1^2');

it returns 1+1

Upvotes: 0

Views: 83

Answers (2)

tckmn
tckmn

Reputation: 59363

This is because [^xyz] means "not x, y, or z." ^ is the "not" operator in character classes ([...]). To fix this, simply escape it (one backslash to escape the ^, and another to escape the first backslash since it's in a string and it's a special character):

var regex = new RegExp('[0-9]+[\\^]{1}[0-9]+');

Also, you don't need to use character classes and the {1} if you only have one character; just do this:

var regex = new RegExp('[0-9]+\\^[0-9]+');

Finally, one more improvement - you can use literal regular expression syntax (/.../) so you don't need two backslashes:

var regex = /[0-9]+\^[0-9]+/;

Fiddle

Upvotes: 6

Marc B
Marc B

Reputation: 360872

[^] in regex terms is a character class ([]) that's been inverted (^). e.g. [^abc] is "any character that is NOT a, b, or c". You need to escape the carat: [\^].

As well, {1} is redundant. Any character class or individual character in a regex has an implied {1} on it, so /a{1}b{1}c{1}/ is just a very verbose way of saying /abc/.

As well, a single-char character class is also redundant. /[a]/ is exactly the same as /a/.

Upvotes: 4

Related Questions