How to check for either uppercase OR lowercase letters with a regex

Question

I would like to check if there is any occurrence of an uppercase or lowercase string in this:

test strings

1a
2A
3aC

js

const str = '1a'
/[a-z]/.test(str) //Pass
/[a-z][A-Z]/.test(str) //Fail
/[a-z]/.test(str) //Pass

`[a-z][A-Z]` only matches one lower case letter followed by one upper case letter. — some, Jan 12 '20 at 11:20
Thnk you for the downvote, please could you provide me with some information as to why you have closed this so I can improve the question. — Jamie Hutber, Jan 12 '20 at 14:59

score 1 · Answer 1 · answered Jan 12 '20 at 11:17

1

Unless there are some edge cases you are worried about....

[a-zA-Z]

should work

answered Jan 12 '20 at 11:17

ruskibenya

19
4

score 1 · Accepted Answer · answered Jan 12 '20 at 11:20

[a-z] means 1 lowercase letter. [A-Z] means 1 uppercase letter. [a-z][A-Z] means 1 lowercase letter followed by 1 uppercase letter. [a-zA-Z] means 1 lowercase or uppercase letter.

To check for "3aC" you might want [0-9][a-zA-Z]+. The "+ means one or more lowercase or uppercase letters.

How to check for either uppercase OR lowercase letters with a regex

test strings

js

2 Answers2