WhizLabs Regex Question

[Edisandro Bessa]

Hi guys,

Can anyone explain how the below code works ?

From within main ...
 
String thePattern = "(?i)ill\\d";
Pattern pattern = Pattern.compile(thePattern);
String target = "Jack and JILL1 WENT UP THE hill2";
Matcher matcher = pattern.matcher(target);
System.out.println(matcher.replaceAll("xxxx"));

Thanks.

[Tamara Lopez]

Hi,
This question confused me too
(?i) turns on case insensitivity - so it will find any sequence of ill or ILL followed by a number. If you take out the (?i) it will only replace the hill2 bit.
I dont think we need to know the case insensitivity one for the exam.... there are a lot of questions that seem to have extra things in whizlabs.

[Edisandro Bessa]

Sure Tamara,

There's extra things charged in WhizLabs simulator.

I was able to understand how the "ill\\d" pattern works but I was unable to determine how the pattern "(?i)" works.

So, let's concentrate our analisys in "(?i)" pattern. Could you please Tamara explain step-by-step how the "(?i)" pattern works ?

As far as I know the pattern "?" means zero or one occurrences, so I'm unable to determine how can it mean about Case Sensitive.

Thanks.

[Tamara Lopez]

I just looked it up and its what it said. To mean one or zero it would be after the character: eg: \\d* or \\d? or ([a-bA-b])+
Check for eg this page out:
http://www.regular-expressions.info/java.html

if you had i? that would mean zero or one i. or (i)?

[Joyce Lee]

Hi guys,

(?i) is an embedded flag expression.

Check out the following page for more info:
http://java.sun.com/docs/books/tutorial/extra/regex/pattern.html

Joyce

[Edisandro Bessa]

Oh yeah. Now I see.

Embedded Flag Expression. That's the point.

Thank you so much for your prompt replies.