字符串的正则表达式仅包含小写字母

Question

Hi I am trying to find a regEx which only accepts lower case letters nothing else,

I tired few options nothing worked, Can some one please guide me :

here are the expressions I tried :

(?=.*[a-z])--> this is not working if we have "aaaAA"

[a-z]+^[A-Z]

^[A-Z]+[a-z]+^[A-Z]

Please help me.

Answer 1

Did you try just [az]+

See example here: https://regex101.com/r/wCdBue/1

If you want to check if whole line / text contains only lowercase letter you should wrap your regex with ^$ like this: ^[az]+$

Example: https://regex101.com/r/T0DHY4/1

Answer 2

Your solution is nearly correct. The regex must say "[az]+"—include a quantifier, which means that you are not matching a single character, but one or more lowercase characters.

String regex = "[az]+";

Here is a quantifier regex link. http://docs.oracle.com/javase/tutorial/essential/regex/quant.html

Answer 3

It's working for me like this:

  String line = "aaaA";
  System.out.println(line.matches("^[a-z]+$")); //false
  line = "aaaa";
  System.out.println(line.matches("^[a-z]+$")); //true