Question

I have a string of format NSString *CalculationFormula = @”((Col(202)/Col(201)-1)*100″;
I need to replace all occurrences of Col(number) with ABC(number * 10)

Please help …

Thanks,
Ben

Answer 1

There’s some ambiguity in the desired results. For example, should the result be “ABC(202 * 10)” or “ABC(2020)”? I’m going to assume the latter. Since regex is fairly generic, here’s a Perl snippet that accomplishes what I think you want, followed by its translation into Cocoa. I’ve given both, because it’s much easier to see what’s going on there before moving onto NSRegularExpression because the latter has so many more escapes in the pattern.

Perl version:

#!/usr/bin/perl -w
use strict;


my $search_text = "((Col(202)/Col(201)-1)*100";

$search_text =~ s|Col\((?P<num>\d+)\)|ABC($+{num}0)|g;
print $search_text;

Prints: ((ABC(2020)/ABC(2010)-1)*100

So, the matching pattern is Col\((?P<num>\d+)\) and the substitution pattern ABC($+{num}0

Cocoa version:

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
    NSAutoreleasePool *p = [[NSAutoreleasePool alloc] init];

    NSRegularExpression *regex = nil;
    regex = [NSRegularExpression regularExpressionWithPattern:@"Col\\((\\d+)\\)" options:NSRegularExpressionCaseInsensitive error:nil];
    NSString *searchText = @"((Col(202)/Col(201)-1)*100";
    NSString *newText = [regex stringByReplacingMatchesInString:searchText options:0 range:NSMakeRange(0,[searchText length]) withTemplate:@"ABC($10)"];
    NSLog(@"new = %@",newText);
    [p release];
}

Logs:

2012-09-18 12:30:26.880 Untitled[22405:707] new = ((ABC(2020)/ABC(2010)-1)*100

Now, if my original assumption was wrong and you literally want “num * 10” in the result,then the substitution pattern is:

@"ABC($1 * 10)"