如何从NSString的右端删除空格？

| 这将删除字符串两端的空白： 
NSString *newString = [oldString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
如何从字符串的右端删除空格？ 更新：接受的答案中的代码现在是SSToolkit的一部分。好极了！     
2019-12-09 5 条评论
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没有找到相关结果

    已邀请:

    桑娠贯涤

    更新：快速基准测试表明，基于Max和我的Matt自己的改编效果最佳。 
    @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
    然后： 
    NSString *trimmedString = [yourString stringByTrimmingTrailingCharactersInSet:[NSCharacterset whitespaceAndNewlineCharacterSet]];
    或领先的空格： 
    NSString *trimmedString = [yourString stringByTrimmingLeadingCharactersInSet:[NSCharacterset whitespaceAndNewlineCharacterSet]];
    它以抽象的方式实现，因此您可以将其与任何可能的
    NSCharacterSet
    一起使用，
    whitespaceAndNewlineCharacterSet
    只是其中之一。 为了方便起见，您可能需要添加以下包装方法： 
    - (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]];
}
    编辑：使用charBuffer恢复为初始版本，以获得更好的性能。     
    2019-12-09 0 0
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    田眯衅

    在@Regexident和@Max的答案的基础上，我想出了以下方法： 
    @implementation NSString (SSToolkitAdditions)

#pragma mark Trimming Methods

- (NSString *)stringByTrimmingLeadingCharactersInSet:(NSCharacterSet *)characterSet {
    NSRange rangeOfFirstWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]];
    if (rangeOfFirstWantedCharacter.location == NSNotFound) {
        return @\"\";
    }
    return [self substringFromIndex:rangeOfFirstWantedCharacter.location];
}

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

- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
    NSRange rangeOfLastWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]
                                                               options:NSBackwardsSearch];
    if (rangeOfLastWantedCharacter.location == NSNotFound) {
        return @\"\";
    }
    return [self substringToIndex:rangeOfLastWantedCharacter.location+1]; // non-inclusive
}

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

@end
    这是GHUnit测试，这些测试当然都可以通过： 
    @interface StringCategoryTest : GHTestCase
@end

@implementation StringCategoryTest

- (void)testStringByTrimmingLeadingCharactersInSet {
    NSCharacterSet *letterCharSet = [NSCharacterSet letterCharacterSet];
    GHAssertEqualObjects([@\"zip90210zip\" stringByTrimmingLeadingCharactersInSet:letterCharSet], @\"90210zip\", nil);
}

- (void)testStringByTrimmingLeadingWhitespaceAndNewlineCharacters {
    GHAssertEqualObjects([@\"\" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @\"\", nil);
    GHAssertEqualObjects([@\"\\n \\n \" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @\"\", nil);
    GHAssertEqualObjects([@\"\\n hello \\n\" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @\"hello \\n\", nil);
}

- (void)testStringByTrimmingTrailingCharactersInSet {
    NSCharacterSet *letterCharSet = [NSCharacterSet letterCharacterSet];
    GHAssertEqualObjects([@\"zip90210zip\" stringByTrimmingTrailingCharactersInSet:letterCharSet], @\"zip90210\", nil);
}

- (void)testStringByTrimmingTrailingWhitespaceAndNewlineCharacters {
    GHAssertEqualObjects([@\"\" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @\"\", nil);
    GHAssertEqualObjects([@\"\\n \\n \" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @\"\", nil);
    GHAssertEqualObjects([@\"\\n hello \\n\" stringByTrimmingTrailingWhitespaceAndNewlineCharacters], @\"\\n hello\", nil);
}

@end
    我向SSToolkit提交了GitHub pull请求，其中添加了这些方法。     
    2019-12-09 0 0
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    犁攀富 

    NSString* str = @\"hdskfh   dsakjfh akhf kasdhfk asdfkjash fkadshf1234        \";
NSRange rng = [str rangeOfCharacterFromSet: [NSCharacterSet characterSetWithCharactersInString: [str stringByReplacingOccurrencesOfString: @\" \" withString: @\"\"]] options: NSBackwardsSearch];
str = [str substringToIndex: rng.location+1];
        
    2019-12-09 0 0
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    咳累录酬

    需要略微更改以解决最后一个非跟踪字符为多字节的情况： 
    - (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
    NSRange rangeOfLastWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]
                                                               options:NSBackwardsSearch];
    if (rangeOfLastWantedCharacter.location == NSNotFound) {
        return @\"\";
    }
    return [self substringToIndex:rangeOfLastWantedCharacter.location + rangeOfLastWantedCharacter.length]; // non-inclusive
}
        
    2019-12-09 0 0
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