I don't know how to create a regular expression in JavaScript or jQuery.
I want to create a regular expression that will check if a string contains only characters between a-z and A-Z with any arrangement.
EDIT
When I tried to make regex
/^[a-zA-Z\s]+$/
to accept white spaces as well. It is not working. What could be the mistake?
I am testing my regular expression at JavaScript RegExp Example: Online Regular Expression Tester.
This question is related to
javascript
jquery
regex
/^[a-zA-Z]*$/
Change the *
to +
if you don't want to allow empty matches.
Character classes ([...]
), Anchors (^
and $
), Repetition (+
, *
)
The /
are just delimiters, it denotes the start and the end of the regex. One use of this is now you can use modifiers on it.
With POSIX Bracket Expressions (not supported by Javascript) it can be done this way:
/[:alpha:]+/
Any alpha character A to Z or a to z.
or
/^[[:alpha:]]+$/s
to match strictly with spaces.
/^[a-zA-Z]+$/
Off the top of my head.
Edit:
Or if you don't like the weird looking literal syntax you can do it like this
new RegExp("^[a-zA-Z]+$");
Piggybacking on what the other answers say, since you don't know how to do them at all, here's an example of how you might do it in JavaScript:
var charactersOnly = "This contains only characters";
var nonCharacters = "This has _@#*($()*@#$(*@%^_(#@!$ non-characters";
if (charactersOnly.search(/[^a-zA-Z]+/) === -1) {
alert("Only characters");
}
if (nonCharacters.search(/[^a-zA-Z]+/)) {
alert("There are non characters.");
}
The /
starting and ending the regular expression signify that it's a regular expression. The search
function takes both strings and regexes, so the /
are necessary to specify a regex.
From the MDN Docs, the function returns -1
if there is no match.
Also note: that this works for only a-z, A-Z. If there are spaces, it will fail.
This /[^a-z]/g
solves the problem.
function pangram(str) {
let regExp = /[^a-z]/g;
let letters = str.toLowerCase().replace(regExp, '');
document.getElementById('letters').innerHTML = letters;
}
pangram('GHV 2@# %hfr efg uor7 489(*&^% knt lhtkjj ngnm!@#$%^&*()_');
_x000D_
<h4 id="letters"></h4>
_x000D_
Source: Stackoverflow.com