从 NSString 的末尾修剪空格

Question

我需要删除字符串末尾的空格。我怎样才能做到这一点？ 示例：如果字符串为"Hello "，则它必须变为"Hello"

Answer 1

取自这里的答案：https://stackoverflow.com/a/5691567/251012

- (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
}

Answer 2

另一种解决方案涉及创建可变字符串：

//make mutable string
NSMutableString *stringToTrim = [@" i needz trim " mutableCopy];

//pass it by reference to CFStringTrimSpace
CFStringTrimWhiteSpace((__bridge CFMutableStringRef) stringToTrim);

//stringToTrim is now "i needz trim"

Answer 3

给你...

- (NSString *)removeEndSpaceFrom:(NSString *)strtoremove{
    NSUInteger location = 0;
    unichar charBuffer[[strtoremove length]];
    [strtoremove getCharacters:charBuffer];
    int i = 0;
    for(i = [strtoremove length]; i >0; i--) {
        NSCharacterSet* charSet = [NSCharacterSet whitespaceCharacterSet];
        if(![charSet characterIsMember:charBuffer[i - 1]]) {
            break;
        }
    }
    return [strtoremove substringWithRange:NSMakeRange(location, i  - location)];
}

所以现在就调用它。假设你有一个字符串，前面有空格，后面有空格，而你只想删除末尾的空格，你可以这样称呼它：

NSString *oneTwoThree = @"  TestString   ";
NSString *resultString;
resultString = [self removeEndSpaceFrom:oneTwoThree];

resultString 的末尾将没有空格。

Answer 4

NSString *trimmedString = [string stringByTrimmingCharactersInSet:
                              [NSCharacterSet whitespaceAndNewlineCharacterSet]];
//for remove whitespace and new line character

NSString *trimmedString = [string stringByTrimmingCharactersInSet:
                              [NSCharacterSet punctuationCharacterSet]]; 
//for remove characters in punctuation category

还有很多其他的字符集。根据您的要求自行检查。

Answer 5

在 Swift 中仅从字符串的开头和结尾删除空格：

斯威夫特 3

string.trimmingCharacters(in: .whitespacesAndNewlines)

以前的 Swift 版本

string.stringByTrimmingCharactersInSet(.whitespaceAndNewlineCharacterSet()))

Answer 6

Swift 版本

只修剪字符串末尾的空格：

private func removingSpacesAtTheEndOfAString(var str: String) -> String {
    var i: Int = countElements(str) - 1, j: Int = i

    while(i >= 0 && str[advance(str.startIndex, i)] == " ") {
        --i
    }

    return str.substringWithRange(Range<String.Index>(start: str.startIndex, end: advance(str.endIndex, -(j - i))))
}

修剪字符串两边的空格：

var str: String = " Yolo "
var trimmedStr: String = str.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())

Answer 7

这将仅删除您选择的尾随字符。

func trimRight(theString: String, charSet: NSCharacterSet) -> String {

    var newString = theString

    while String(newString.characters.last).rangeOfCharacterFromSet(charSet) != nil {
        newString = String(newString.characters.dropLast())
    }

    return newString
}

Answer 8

在 Swift 中

从字符串的两侧修剪空格和换行符：

var url: String = "\n   http://example.com/xyz.mp4   "
var trimmedUrl: String = url.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())

Answer 9

Objective-C 中只修剪一端而不是两端的简单解决方案：

@implementation NSString (category)

/// trims the characters at the end
- (NSString *)stringByTrimmingSuffixCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger i = self.length;
    while (i > 0 && [characterSet characterIsMember:[self characterAtIndex:i - 1]]) {
        i--;
    }
    return [self substringToIndex:i];
}

@end

还有一个对称实用程序，仅用于修剪开头：

@implementation NSString (category)

/// trims the characters at the beginning
- (NSString *)stringByTrimmingPrefixCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger i = 0;
    while (i < self.length && [characterSet characterIsMember:[self characterAtIndex:i]]) {
        i++;
    }
    return [self substringFromIndex:i];
}

@end

Answer 10

要修剪所有尾随空白字符（我猜这实际上是您的意图），以下是一种非常简洁明了的方法。

斯威夫特 5：

let trimmedString = string.replacingOccurrences(of: "\\s+$", with: "", options: .regularExpression)

目标-C：

NSString *trimmedString = [string stringByReplacingOccurrencesOfString:@"\\s+$" withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, string.length)];

一行，带有一点正则表达式。

Answer 11

这里描述了解决方案：How to remove whitespace from right end of NSString?

将以下类别添加到 NSString：

- (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]];
}

你就这样使用它：

[yourNSString stringByTrimmingTrailingWhitespaceAndNewlineCharacters]

Answer 12

我想出了这个函数，它的行为基本上与 Alex 的回答中的一个相似：

-(NSString*)trimLastSpace:(NSString*)str{
    int i = str.length - 1;
    for (; i >= 0 && [str characterAtIndex:i] == ' '; i--);
    return [str substringToIndex:i + 1];
}

whitespaceCharacterSet 除了空格本身还包括制表符，在我的情况下无法出现。所以我想一个简单的比较就足够了。

Answer 13

let string = "测试修剪后的字符串"

要删除空格和换行，请使用以下代码：-

让 str_trimmed = yourString.trimmingCharacters(in: .whitespacesAndNewlines)

仅从字符串中删除空格，请使用以下代码：-

让 str_trimmed = yourString.trimmingCharacters(in: .whitespaces)

Answer 14

NSString* NSStringWithoutSpace(NSString* string)
{
    return [string stringByReplacingOccurrencesOfString:@" " withString:@""];
}