[Solved] How to remove common letters in two Strings in iOS SDK? [duplicate]

by


You can proceed similar as in this answer
to your previous question:

NSString *string1 = @"optimusprime";
NSString *string2 = @"dejathoras";

// Combine strings:
NSString *combined = [string1 stringByAppendingString:string2];

// Now remove duplicate characters:
NSMutableString *result = [combined mutableCopy];
[result enumerateSubstringsInRange:NSMakeRange(0, [result length])
               options:NSStringEnumerationByComposedCharacterSequences
            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                // Check if current character already occurred at an earlier location:
                NSRange previousRange = [result rangeOfString:substring
                                      options:0
                                    range:NSMakeRange(0, substringRange.location)];
                if (previousRange.location != NSNotFound) {
                    [result deleteCharactersInRange:substringRange];
                }
            }];
NSLog(@"%@", result);

Output: optimusredjah

EDIT: The above solution does not scale very well. Storing duplicate characters
in a dictionary, as suggested in @waf’s answer, or in a set, is probably better:

NSMutableString *result = [combined mutableCopy];
NSMutableSet *chars = [NSMutableSet set];
[result enumerateSubstringsInRange:NSMakeRange(0, [result length])
               options:NSStringEnumerationByComposedCharacterSequences
            usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                if ([chars containsObject:substring]) {
                    [result deleteCharactersInRange:substringRange];
                } else {
                    [chars addObject:substring];
                }

            }];

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solved How to remove common letters in two Strings in iOS SDK? [duplicate]