检查字符串是否只包含字母空格和引号（最好不包含正则表达式）

Question

I am trying to check if a string has only letters (both uppercase and lowercase), spaces and quotes (both double and single) in it. I can't quite come up with an elegant way of doing this. The only thing I could come up with is making a list of the allowed characters and checking if each character of the string is in that list.

Answer 1

You can do it like this:

str.matches("[a-zA-Z\\s\'\"]+");

You said preferably no REGEX, but you wanted an elegant way. In my opinion this would be an easy, short and elegant way to get what you want.

Answer 2

If you do not want REGEX, you may check character by character in the String:

public static boolean onlyLetterSpaceQuotes(String str){
    for(int x=0; x<str.length(); x++){
        char ch = str.charAt(x);
        if (!((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || ch == ' ' 
            || ch == '\'' || ch == '\"'))
            return false;               
    }
    return true;            
}

Test:

System.out.println(onlyLetterSpaceQuotes("abc \"A\'BC"));
System.out.println(onlyLetterSpaceQuotes("abc \"A\'BC123")); 

Output:

true
false