去空格 whitespaceAndNewlineCharacterSet和過濾字串

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 一、過濾字串

　　可以使用stringByTrimmingCharactersInSet函數過濾字串中的特殊符號

 

　　首先自己定義一個NSCharacterSet, 包含需要去除的特殊符號

NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@"@／：；（）￥「」＂、[]{}#%-*+=_//|~＜＞$€^?‘@#$%^&*()_+‘/"""];由於NSString中有全形符號和半形符號, 因此有些符號要包括全形和半形的然後調用stringByTrimmingCharactersInSetNSString *trimmedString = [string stringByTrimmingCharactersInSet:set];trimmedString就是過濾後的字串

二、去除空格

　　1.去掉兩端的空格

  1 [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]   

 

　　2.去掉多餘的空格

1 NSString *str = @"    this     is a    test    .   ";  2       3     NSCharacterSet *whitespaces = [NSCharacterSet whitespaceCharacterSet];  4     NSPredicate *noEmptyStrings = [NSPredicate predicateWithFormat:@"SELF != ‘‘"];  5       6     NSArray *parts = [str componentsSeparatedByCharactersInSet:whitespaces];  7     NSArray *filteredArray = [parts filteredArrayUsingPredicate:noEmptyStrings];  8     str = [filteredArray componentsJoinedByString:@" "]; 

 

　　3.去掉所有空格

 1 [str stringByReplacingOccurrencesOfString:@" " withString:@""]  

 

　　4.去掉最左邊的空格  和  去掉最右邊的空格

@interface NSString (TrimmingAdditions)  - (NSString *)stringByTrimmingLeftCharactersInSet:(NSCharacterSet *)characterSet ;  - (NSString *)stringByTrimmingRightCharactersInSet:(NSCharacterSet *)characterSet ;  @end    @implementation NSString (TrimmingAdditions)    - (NSString *)stringByTrimmingLeftCharactersInSet:(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 *)stringByTrimmingRightCharactersInSet:(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  

    例如：NSLog(@"%@",[@"abc 123 " stringByTrimmingRightCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]);

    　　：NSLog(@"%@",[@"0.012300" stringByTrimmingRightCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"0"]])；

 

去空格 whitespaceAndNewlineCharacterSet和過濾字串