How to recognize numbers in a string using JS?

Question

If we have a string, say

'1, 2, 3, 4'
'1, 2, 3 GO!'
'ZOMG THE %^*@#$(*^ ZOMBIES ARE COMING!!11!!1!'

then how do I recognize that its has numbers and return true?

I need it because while using,

if(input == input.toUpperCase())

if a number is entered this condition returns true, so need to add an elegant way to stop the numbers from passing this condition.

Edit1: The string is indeed comma separated, I already have googled ways that recognize non comma separated strings as numbers.

Edit2: Added more examples of what I need to pass.

Does regex meet your requirements? What other strings do you need to be able to parse? — Brad
– Brad, Commented Oct 5, 2014 at 18:39
@Brad Regex is my last resort, all alphabets, special characters and umlauts. — Prakash Wadhwani
– Prakash Wadhwani, Commented Oct 5, 2014 at 18:42
@PrakashWadhwani Why would regex be your last resort if it does exactly what you want? And, I'm saying that if you want to parse a wide variety of strings, you should provide more than one example in your question. Otherwise, it isn't clear what you're trying to do. — Brad
– Brad, Commented Oct 5, 2014 at 18:43
@Brad its classical problem called Bob, you can read about it here, jsfiddle.net/pzoc03vm and the tests that need to be passed are, jsfiddle.net/7yzfpor9 — Prakash Wadhwani
– Prakash Wadhwani, Commented Oct 5, 2014 at 18:45

Community · Accepted Answer · 2017-05-23 10:25:23Z

1

Regular expressions are appropriate for this:

var str = "(1, 2, 3, 4)";
var containsNumber = /\d/.test(str);      // true

Here, \d is a regular expression that will match if your string contains a digit anywhere.

Ok, looks like you need to look for lowercase letters... If there's any lowercase letter it shouldn't be considered yelling.

var str = "(1, 2, 3, 4)";
var containsLowercaseLetters = /[a-z]/.test(str);      // false

This will only work for latin letters though. In your case, it may be simpler to just state:

var isYelling = (input == input.toUpperCase()) && (input != input.toLowerCase());

edited May 23, 2017 at 10:25

CommunityBot

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answered Oct 5, 2014 at 18:41

Lucas Trzesniewski

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4 Comments

Prakash Wadhwani Over a year ago

Ok, although it works with numbers only, but I need to also check if there is an alphabet with them, then it has to fail the test.

Brad Over a year ago

@PrakashWadhwani Update your question with an appropriate test case.

Lucas Trzesniewski Over a year ago

Updated. Beware of asking X-Y problems in the future ;)

Prakash Wadhwani Over a year ago

Aha! Exactly what I was looking for, simple and elegant without any confusing regex, toLowerCase beautifully rejects numbers, I wish I had thought that myself! Thanks Lucas!

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