【iOS】去除字符串首尾空格或某字符

在iOS的實際開發中，常會出現需要去除空格的情況，總結有三種情況：

• 去除字符串首尾連續字符（如空格）；
• 去除字符串首部連續字符（如空格）；
• 去除字符串尾部連續字符（如空格）；

去除字符串首尾連續字符（如空格）

 NSString *a = @" a sdf "; [a stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; 

去除字符串首部連續字符（如空格）；

 NSString *a = @" a sdf "; NSString *leftResult = [a stringByTrimmingLeftCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]; 

#import "NSString+util.h" @implementation NSString (util) - (NSString *)stringByTrimmingLeftCharactersInSet:(NSCharacterSet *)characterSet { NSUInteger location = 0; NSUInteger length = [self length]; unichar charBuffer[length]; [self getCharacters:charBuffer range:NSMakeRange(0, length)]; for (NSInteger i = 0; i < length; i++) { if (![characterSet characterIsMember:charBuffer[i]]) { location = i; break; } } return [self substringWithRange:NSMakeRange(location, length - location)]; } 

去除字符串尾部連續字符（如空格）；

NSString *a = @" a sdf "; NSString *rightResult = [a stringByTrimmingRightCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]; 

- (NSString *)stringByTrimmingRightCharactersInSet:(NSCharacterSet *)characterSet { NSUInteger length = [self length]; unichar charBuffer[length]; [self getCharacters:charBuffer range:NSMakeRange(0, length)]; NSUInteger subLength = 0; for (NSInteger i = length; i > 0; i--) { if (![characterSet characterIsMember:charBuffer[i - 1]]) { subLength = i; break; } } return [self substringWithRange:NSMakeRange(0, subLength)]; }