如何删除 NSString 右端的空格？

这会删除字符串两端的空格：

NSString *newString = [oldString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

如何删除字符串右端的空格？

更新：代码来自接受的答案 https://stackoverflow.com/questions/5689288/how-to-remove-whitespace-from-right-end-of-nsstring/5691567#5691567现在是的一部分SS工具包 https://github.com/samsoffes/sstoolkit/blob/master/SSToolkit/NSString+SSToolkitAdditions.m#L288-318. Yay!

UPDATE:快速基准测试表明马特自己的改编 https://stackoverflow.com/questions/5689288/how-to-remove-whitespace-from-right-end-of-nsstring/5691567#5691567， 基于Max' https://stackoverflow.com/questions/5689288/how-to-remove-whitespace-from-right-end-of-nsstring/5689826#5689826和我的，表现最好。

@implementation NSString (TrimmingAdditions)

- (NSString *)stringByTrimmingLeadingCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger location = 0;
    NSUInteger length = [self length];
    unichar charBuffer[length];    
    [self getCharacters:charBuffer];

    for (location; location < length; location++) {
        if (![characterSet characterIsMember:charBuffer[location]]) {
            break;
        }
    }

    return [self substringWithRange:NSMakeRange(location, length - location)];
}

- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger location = 0;
    NSUInteger length = [self length];
    unichar charBuffer[length];    
    [self getCharacters:charBuffer];

    for (length; length > 0; length--) {
        if (![characterSet characterIsMember:charBuffer[length - 1]]) {
            break;
        }
    }

    return [self substringWithRange:NSMakeRange(location, length - location)];
}

@end

进而：

NSString *trimmedString = [yourString stringByTrimmingTrailingCharactersInSet:[NSCharacterset whitespaceAndNewlineCharacterSet]];

或者对于前导空格：

NSString *trimmedString = [yourString stringByTrimmingLeadingCharactersInSet:[NSCharacterset whitespaceAndNewlineCharacterSet]];

它以抽象方式实现，因此您可以将它与任何可能的方式一起使用NSCharacterSet, whitespaceAndNewlineCharacterSet只是其中之一。

为了方便起见，您可能需要添加这些包装方法：

- (NSString *)stringByTrimmingLeadingWhitespace {
    return [self stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}

- (NSString *)stringByTrimmingTrailingWhitespace {
    return [self stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}

- (NSString *)stringByTrimmingLeadingWhitespaceAndNewline {
    return [self stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}

- (NSString *)stringByTrimmingTrailingWhitespaceAndNewline {
    return [self stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}

Edit:使用 charBuffer 恢复到初始版本以获得更好的性能。