修剪NSString结尾的空格
我需要从string的末尾删除空格。 我怎样才能做到这一点？ 例如：如果string是"Hello "它必须变成"Hello"
使用-stringByTrimmingCharactersInSet：
NSString *string = @" this text has spaces before and after "; NSString *trimmedString = [string stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceCharacterSet]];
（这将修剪两端的空白字符）。
Swift 3
let string = " this text has spaces before and after " let trimmedString = string.trimmingCharacters(in: .whitespacesAndNewlines)
另一个解决scheme涉及创build可变string
//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"
干得好…
- (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string，前面有空格，最后是空格，你只是想删除末尾的空格，你可以这样调用它：
NSString *oneTwoThree = @" TestString "; NSString *resultString; resultString = [self removeEndSpaceFrom:oneTwoThree];
resultString将在最后没有空格。
要从Swift中的string的开头和结尾删除空格：
Swift 3
string.trimmingCharacters(in: .whitespacesAndNewlines)
以前的Swift版本
string.stringByTrimmingCharactersInSet(.whitespaceAndNewlineCharacterSet()))
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CharacterSets。 根据您的要求自己检查一下。
Swift版本
只修剪string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string两边的空格：
var str: String = " Yolo " var trimmedStr: String = str.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
这将只删除您select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
从string的两端修剪空格和换行符：
var url: String = "\n http://example.com/xyz.mp4 " var trimmedUrl: String = url.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
我想出了这个函数，它基本上和Alex在答复中的performance类似：
-(NSString*)trimLastSpace:(NSString*)str{ int i = str.length - 1; for (; i >= 0 && [str characterAtIndex:i] == ' '; i--); return [str substringToIndex:i + 1]; }
whitespaceCharacterSet本身除了空格本身也包含tab字符，这在我的情况下是不能出现的。 所以我想一个简单的比较就足够了。
一个简单的解决scheme，只修剪一端，而不是两端在objective-c：
@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
还有一个对称的工具，仅用于修改开头：
@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
NSString* NSStringWithoutSpace(NSString* string) { return [string stringByReplacingOccurrencesOfString:@" " withString:@""]; }
