比较字符串忽略开头或结尾处的空格

Posted 2021-04-07

我是ios开发的新手，我正在寻找一种解决方案来比较两个String，忽略开头或结尾处的空格。例如，“Hello”==“Hello”应该返回true。

我已经搜索过一个解决方案，但我在Swift中找不到任何东西。谢谢

答案

 NSString *string1 = @" Hello";
 //remove(trim) whitespaces
 string1 = [string1 stringByReplacingOccurrencesOfString:@" " withString:@""];

 NSString *string2 = @"Hello ";
 //remove(trim) whitespaces
 string2 = [string1 stringByReplacingOccurrencesOfString:@" " withString:@""]

 // compare strings without whitespaces
 if ([string1 isEuqalToString:string2]) {
 }

所以如果你想直接使用它 -

if ([[yourString1 stringByReplacingOccurrencesOfString:@" " withString:@""] isEuqalToString:[yourString2 stringByReplacingOccurrencesOfString:@" " withString:@""]]) {
// Strings are compared without whitespaces.
}

上面将删除你的字符串的所有空格，如果你只想删除前导和尾随空格，那么有几个帖子已经可用，你可以创建一个字符串类别，如下面的堆栈溢出帖子所述 - How to remove whitespace from right end of NSString?

@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

现在，一旦你有了可用的方法，你可以在你的字符串上调用这些方法来修剪前导和尾随空格，如 -

 // trim leading chars
 yourString1 = [yourString1 stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
// trim trainling chars
yourString1 = [yourString1 stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

// trim leading chars
 yourString2 = [yourString2 stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
// trim trainling chars
yourString2 = [yourString2 stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

// compare strings
if([yourString1 isEqualToString: yourString2]) {

}

另一答案

我建议你先用这个Swift代码修剪字符串中的空格：

stringToTrim.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())

另一答案

适用于Swift 3.0+

在比较之前使用.trimmingCharacters(in: .whitespaces)或.trimmingCharacters(in: .whitespacesAndNewlines)

另一答案

在Swift 4中 在任何String类型变量上使用它。

extension String {
    func trimWhiteSpaces() -> String {
        let whiteSpaceSet = NSCharacterSet.whitespaces
        return self.trimmingCharacters(in: whiteSpaceSet)
    }
}

并称之为这样

yourString.trimWhiteSpaces()