NSString去除两边空格字符，like trim()[转]

NSString *cleanString = [dirtyString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

还有就是去除多于的空格，如下：

NSString *theString = @" Hello this is a long string! ";

NSCharacterSet *whitespaces = [NSCharacterSet whitespaceCharacterSet];

NSPredicate *noEmptyStrings = [NSPredicate predicateWithFormat:@"SELF != ''"];

NSArray *parts = [theString componentsSeparatedByCharactersInSet:whitespaces];

NSArray *filteredArray = [parts filteredArrayUsingPredicate:noEmptyStrings];

theString = [filteredArray componentsJoinedByString:@" "];