4 replies to this topic

[eman ahmed]

how can I know that the string contian only the alphabatic from (a....z)
and (A....Z) and doesn't contain any symbol like ( ,-'
I want to do that by scan astring from left to right and check each character in it by
if(.........)
now what's the condition I should write it

[Alexander]

If you're wanting to scan, instead of relying on regex here is a simple option:

private boolean onlyLetters(final String s) {
  final char[] chars = s.toCharArray();
  for (int x = 0; x < chars.length; x++) {      
    final char c = chars[x];
    if ((c >= 'a') && (c <= 'z')) continue; // lowercase
    if ((c >= 'A') && (c <= 'Z')) continue; // uppercase
    return false;
  }  
  return true;
}

If you're wanting to use simple regular expressions:

boolean onlyLetters(String str) {
   return str.matches("^[a-zA-Z]+$");
}

[wim DC]

I see that you use ^ and $ in the regex. I see that a lot, but what does it do? I think i've read that $ matches a endline or newline char, but the ^?

That was also an issue in this thread: http://forum.codecal...al-c-regex.html

[Alexander]

oxano said:

I see that you use ^ and $ in the regex. I see that a lot, but what does it do? I think i've read that $ matches a endline or newline char, but the ^?

^: Field starts with.
$: Field ends with.

If they're not used it will simply match "if it contains [a-zA-Z]" and not "if it only contains [a-zA-Z]"

[wim DC]

Oh, okay. I still don't get what was wrong in the c# tut then :s

Edit: oh wait, i do now :D nevermind