Re: Regex doesn't recognize single quote

Roedy Green <>
Sat, 07 Jan 2012 14:41:38 -0800
On 7 Jan 2012 11:42:26 GMT, (Stefan Ram) wrote,
quoted or indirectly quoted someone who said :

That is not what a regex is for.

 How do you know what it is for?

Regexes are for searching for patterns. Transforming or deleting
characters is much simpler done with a for loop.

How do I know what a regex is for? I am familiar with the API. I have
attempted to use them for various purposes and discovered they were
suitable for some and not for others.

Just use a StringBuilder the length of your String. Then
loop through the chars with charAt. If the character is a
' or \w, ignore it, else append. If it gets complex, use a
switch or if it gets really complicated use a BitSet.

 This might be needless (as far as we know right now)
 optimization bloating the code reducing its readability and
 low-level thinking, which might be required sometimes, but
 does not serve as a general rule. Still it is nice to know
 how it could be done if required.

What is your simpler implementation?

/** remove ' and \w from string
  * @param s string to process
  * @return string without ' or \w
private static String scrunch( final String s )
final Stringbuilder sb = new StringBuilder( s.length() );
for (int i=0; i<s.length(); i++ )
  char c = s.charAt(i);
  if ( !( c = '\'' || c = '\w' ) )
     sb.append ( c );
return sb.toString();
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