在Objective-C中大写或更改NSString的大小写

Question

我想知道如何大写在一个对象中找到的字符串NSMutableArray.

一个NSArray包含字符串'April'索引2.
我想这是改变'APRIL'.

这样简单吗？

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

Answer 1

你走了:

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

顺便说一下:
"april"被lowercase➔ [NSString的lowercaseString]
"APRIL"是UPPERCASE➔ [的NSString uppercaseString]
"April May"是Capitalized/Word Caps➔ [的NSString capitalizedString]
"April may"是Sentence caps➔ (方法缺失;见下文解决方法)

因此,你想要的是" 大写 ",而不是" 大写 ".;)

至于"句子上限",必须记住,通常"句子"的意思是"整个字符串".如果你想要真正的句子,请使用下面的第二种方法,否则第一种方法:

@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

Answer 2

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

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

您还可以使用lowercaseString和capitalizedString