Support code for http://weblog.bignerdranch.com/708-string-and-string-what-is-string/

string-fun.m

#import <Foundation/Foundation.h>

// clang -Weverything -framework Foundation -o string-fun string-fun.m

int main (void) {
    @autoreleasepool {

        {
            // Split and join
            NSString *splitString = @"hello:-(there:-(everybody";
            NSArray *split = [splitString componentsSeparatedByString: @":-("];
            NSLog (@"split: %@", split);
            
            NSString *joinString = [split componentsJoinedByString: @":-)"];
            
            NSLog (@"%@ -> %@", splitString, joinString);
        }

        {
            // Extract substrings based on index
            NSString *subby = @"whatsoever";
            NSString *first = [subby substringToIndex: 4];   // LEFT$
            NSString *last = [subby substringFromIndex: 6];  // RIGHT$

            NSRange range = NSMakeRange (4, 2);
            NSString *middle = [subby substringWithRange: range];  // MID$

            NSLog (@"%@ -> %@ %@ %@", subby, first, middle, last);
        }

        {
            // Has prefix / suffix
            NSString *tweet = @"@wookiee your pony is looking colorful today!";
            NSLog (@"looking at tweet: '%@'", tweet);
            if ([tweet hasPrefix: @"@"]) NSLog (@"  tweet is a reply");
            if ([tweet hasSuffix: @"!"]) NSLog (@"  tweet is excitable");
            if ([tweet hasSuffix: @"?"]) NSLog (@"  tweet is questionable");
        }

        {
            // Easy concatenation
            NSString *cookie = @"I made you a cookie. ";
            NSString *eated = @"But I eated it";

            NSString *cat = [cookie stringByAppendingString: eated];
            NSLog (@"LOL: %@", cat);

            cat = [@"I made you a cookie. " stringByAppendingString: eated];
            NSLog (@"LOL^2: %@", cat);
        }

        {
            // Quick number conversions.  Skips whitespaceSet and ignores trailing
            // characters.  NSScanner / NSNumberFormatter suggested for more exact
            // parsing of numbers.
            NSArray *intValues =
                [NSArray arrayWithObjects: @"1", @"  2bork", @"\t \t3greeble5",
                         @"-12", @"-", @"", nil];
            for (NSString *scan in intValues) {
                NSLog (@"  %@ -> %d", scan, [scan intValue]);
            }

            NSArray *boolValues =
                [NSArray arrayWithObjects:
                             @"1", @"2", @"y", @"  yEs", @"Yes",
                             @"0", @"n", @"\tNo", @"NO", 
                         @"", @"gronk", nil];
            for (NSString *scan in boolValues) {
                NSLog (@"  %@ -> %d", scan, [scan boolValue]);
            }
        }
    }

    {
        // Common prefix
        NSString *thing1 = @"BigNerdRanch";
        NSString *thing2 = @"Bigbooty, John";
        NSString *commonPrefix = [thing1 commonPrefixWithString: thing2
                                         options: 0];
        NSLog (@"%@ is common between %@ and %@", commonPrefix, thing1, thing2);
    }

    {
        // Capitalization
        NSString *sentence =
            @"fOUr scOrE aND sEveN-yEARs aGo ouR FAthers brouGHT Fourth.";
        NSLog (@"original: %@", sentence);
        NSString *capped = [sentence capitalizedString];
        NSLog (@"  capped: %@", capped);

        NSString *upper = [sentence uppercaseString];
        NSString *lower = [sentence lowercaseString];
        NSLog (@"  upper: %@", upper);
        NSLog (@"  lower: %@", lower);
    }

    {
        // Trimming
        // Remove whitespace from ends of a string
        NSString *original = @"\n \t\t hello there \t\n  \n\n";
        NSString *trimmed =
            [original stringByTrimmingCharactersInSet:
                          [NSCharacterSet whitespaceAndNewlineCharacterSet]];
        
        NSLog (@"trimmed '%@' to '%@'", original, trimmed);
    }

    {
        // Padding and truncating to length
        NSString *original = @"I've got a bad feeling about this ";

        NSString *shorter = [original stringByPaddingToLength: 22
                                      withString: nil
                                      startingAtIndex: 0];
        NSLog (@"  shorter: %@", shorter);

        NSString *leader = [original stringByPaddingToLength: 40
                                     withString: @"."
                                     startingAtIndex: 0];
        NSLog (@"  leader: %@", leader);

        NSString *longer = [original stringByPaddingToLength: 40
                                     withString: @"(:-"
                                     startingAtIndex: 0];
        NSLog (@"  longer: %@", longer);

        NSString *phased = [original stringByPaddingToLength: 40
                                    withString: @"(:-"
                                    startingAtIndex: 1];
        NSLog (@"  phased: %@", phased);

        // Actually using the starting index for something useful

        // These will end up having different characters at the end
        NSString *thing = @"thing";
        NSString *thingy = @"thingy";
        NSString *outOfPhaseThing = [thing stringByPaddingToLength: 30
                                           withString: @"-="
                                           startingAtIndex: 0];
        NSString *outOfPhaseThingy = [thingy stringByPaddingToLength: 30
                                             withString: @"-="
                                             startingAtIndex: 0];
        NSLog (@"%@", outOfPhaseThing);
        NSLog (@"%@", outOfPhaseThingy);
        
        NSString *inPhaseThing = [thing stringByPaddingToLength: 30
                                          withString: @"-="
                                          startingAtIndex: thing.length % 2];
        NSString *inPhaseThingy = [thingy stringByPaddingToLength: 30
                                            withString: @"-="
                                            startingAtIndex: thingy.length % 2];
        NSLog (@"%@", inPhaseThing);
        NSLog (@"%@", inPhaseThingy);
    }
        
    return 0;
} // main