Question

I’d like to create a regular expression that will match and return based on the following criteria:

1) I have N search terms entered by a user

2) I have a body of text.

3) I want to return a list of all the occurrences of all the search terms entered by the user plus surrounding context. I think (\w+\W+){,4}(“, “)(\W+\w+){,4} might work.

4) I don’t know how to use RegexKitLite at all. Do I invoke a RegexKitLite class? or does it interface into NSString somehow?

Answer 1

RegexKitLite defines a category on NSString. To get an array of substrings matching a pattern, use componentsMatchedByRegex:, as shown in the “Creating an Array of Every Match” section of the documentation.

NSArray *words = [NSArray arrayWithObjects:@"brown",@"lazy",nil];
NSString *pattern = [NSString stringWithFormat:@"(\\w+\\W+){0,4}(%@)(\\W+\\w+){0,4}",[words componentsJoinedByString:@"|"]];
NSString *text = @"the quick brown fox jumped over the lazy dog";
NSArray *matches = [text componentsMatchedByRegex:pattern];