IOS 字符串中去除特殊符號 stringByTrimmingCharactersInSet

先上個例子：
NSString * str1 =[nameInput.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
NSString * str2 =[passwdInput.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
[self.delegate loginActionInView:self name:str1 passwd:str2];


轉載自：http://blog.csdn.net/aiyongyyy/article/details/8269546

在ios中 可使用stringByTrimmingCharactersInSet函數過濾字符串中的特殊符號


首先本身定義一個NSCharacterSet, 包含須要去除的特殊符號
   
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@"@／：；（）¥「」＂、[]{}#%-*+=_\\|~＜＞$€^•'@#$%^&*()_+'\""];


因爲NSString中有全角符號和半角符號, 所以有些符號要包括全角和半角的


而後調用stringByTrimmingCharactersInSet


NSString *trimmedString = [string stringByTrimmingCharactersInSet:set];


trimmedString就是過濾後的字符串




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http://blog.sina.com.cn/s/blog_5421851501014xif.html


去除 username中的空格，table newline，nextline 
代碼以下：（三行代碼） 

NSCharacterSet *whitespace = [NSCharacterSet  whitespaceAndNewlineCharacterSet]; 

NSString * username = [mUsernameField  stringValue]; 

username = [username  stringByTrimmingCharactersInSet:whitespace]; 



註釋： 

stringByTrimmingCharactersInSet: 
Returns a new string made by removing from both ends of the receiver characters contained in a given character set. 

whitespaceAndNewlineCharacterSet 
Returns a character set containing only the whitespace characters space (U+0020) and tab (U+0009) and the newline and nextline characters (U+000A–U+000D, U+0085). 

另外能夠用 whitespaceCharacterSet 替換 whitespaceAndNewlineCharacterSet 區別newline nextline 
whitespaceCharacterSet 
Returns a character set containing only the in-line whitespace characters space (U+0020) and tab (U+0009).
 
 
NSString *temptext = [messageTextField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
NSString *text = [temptext stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet ]];
第1行是去除2端的空格
第2行是去除回車