Capitalize or change case of an NSString in Objective-C

问题

I was wondering how to capitalize a string found in an object in an NSMutableArray.

An NSArray contains the string 'April' at index 2.
I want this to be changed to 'APRIL'.

Is there something simple like this?

viewNoteDateMonth.text  = [[displayDate objectAtIndex:2] capitalized];

回答1:

Here ya go:

viewNoteDateMonth.text  = [[displayDate objectAtIndex:2] uppercaseString];

Btw:
"april" is lowercase ➔ [NSString lowercaseString]
"APRIL" is UPPERCASE ➔ [NSString uppercaseString]
"April May" is Capitalized/Word Caps ➔ [NSString capitalizedString]
"April may" is Sentence caps ➔ (method missing; see workaround below)

Hence what you want is called "uppercase", not "capitalized". ;)

As for "Sentence Caps" one has to keep in mind that usually "Sentence" means "entire string". If you wish for real sentences use the second method, below, otherwise the first:

@interface NSString ()

- (NSString *)sentenceCapitalizedString; // sentence == entire string
- (NSString *)realSentenceCapitalizedString; // sentence == real sentences

@end

@implementation NSString

- (NSString *)sentenceCapitalizedString {
    if (![self length]) {
        return [NSString string];
    }
    NSString *uppercase = [[self substringToIndex:1] uppercaseString];
    NSString *lowercase = [[self substringFromIndex:1] lowercaseString];
    return [uppercase stringByAppendingString:lowercase];
}

- (NSString *)realSentenceCapitalizedString {
    __block NSMutableString *mutableSelf = [NSMutableString stringWithString:self];
    [self enumerateSubstringsInRange:NSMakeRange(0, [self length])
                             options:NSStringEnumerationBySentences
                          usingBlock:^(NSString *sentence, NSRange sentenceRange, NSRange enclosingRange, BOOL *stop) {
        [mutableSelf replaceCharactersInRange:sentenceRange withString:[sentence sentenceCapitalizedString]];
    }];
    return [NSString stringWithString:mutableSelf]; // or just return mutableSelf.
}

@end

回答2:

viewNoteDateMonth.text  = [[displayDate objectAtIndex:2] uppercaseString];

Documentation: http://developer.apple.com/library/ios/documentation/Cocoa/Reference/Foundation/Classes/NSString_Class/Reference/NSString.html#//apple_ref/occ/instm/NSString/uppercaseString

You can also use lowercaseString and capitalizedString

回答3:

In case anyone needed the above in swift :

SWIFT 3.0 and above :

this will capitalize your string, make the first letter capital :

viewNoteDateMonth.text  = yourString.capitalized

this will uppercase your string, make all the string upper case :

viewNoteDateMonth.text  = yourString.uppercased()

来源：https://stackoverflow.com/questions/5586756/capitalize-or-change-case-of-an-nsstring-in-objective-c

标签

objective-c

string

cocoa-touch

nsstring

uppercase