我需要从字符串末尾删除空格。我该如何做?
示例:如果字符串是"Hello "
,则必须变为"Hello"
我需要从字符串末尾删除空格。我该如何做?
示例:如果字符串是"Hello "
,则必须变为"Hello"
翻译自这里的答案:https://dev59.com/8G025IYBdhLWcg3w_a6r#5691567
- (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
}
whitespaceAndNewlineCharacterSet
。 - penfoldreturn [self substringToIndex:rangeOfLastWantedCharacter.location + rangeOfLastWantedCharacter.length];
- vinsent另一种解决方案是创建可变字符串:
//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"
这是你需要的...
- (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)];
}
现在只需调用它。假设你有一个字符串,在前面和后面都有空格,你只想去掉末尾的空格,可以像这样调用:
NSString *oneTwoThree = @" TestString ";
NSString *resultString;
resultString = [self removeEndSpaceFrom:oneTwoThree];
resultString
最终将没有末尾的空格。
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
还有许多其他的字符集。根据您的需求自行检查。
在Swift中仅从字符串开头和结尾去除空格:
string.trimmingCharacters(in: .whitespacesAndNewlines)
string.stringByTrimmingCharactersInSet(.whitespaceAndNewlineCharacterSet()))
stringByTrimmigCharactersInSet:
的说明 - “返回一个新字符串,它从接收者两端删除给定字符集中包含的字符。” https://developer.apple.com/reference/foundation/nsstring/1415462-stringbytrimmingcharactersinset?language=objc - lostAtSeaJoshuaSwift版本
仅剪裁字符串末尾的空格:
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))))
}
去除字符串两端的空格:
var str: String = " Yolo "
var trimmedStr: String = str.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
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
}
在Swift中
要从字符串两侧删除空格和换行符:
var url: String = "\n http://example.com/xyz.mp4 "
var trimmedUrl: String = url.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
在Objective-C中只修剪一个端而不是两个端的简单解决方案:
@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
还有一个对称的实用程序,只用于修剪开头:
@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
如果您希望删除所有尾部空格字符(我猜这实际上是您的意图),以下是一种相当简洁干净的方法。
Swift 5:
let trimmedString = string.replacingOccurrences(of: "\\s+$", with: "", options: .regularExpression)
Objective-C:
NSString *trimmedString = [string stringByReplacingOccurrencesOfString:@"\\s+$" withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, string.length)];