先上個(gè)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(zhuǎn)載自：http://blog.csdn.net/aiyongyyy/article/details/8269546

在ios中 可以使用stringByTrimmingCharactersInSet函數(shù)過濾字符串中的特殊符號

首先自己定義一個(gè)NSCharacterSet, 包含需要去除的特殊符號

NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@"@／：；（）￥「」＂、[]{}#%-*+=_\\|~＜＞$€^·'@#$%^&*()_+'\""];

由于NSString中有全角符號和半角符號, 因此有些符號要包括全角和半角的

然后調(diào)用stringByTrimmingCharactersInSet

NSString *trimmedString = [string stringByTrimmingCharactersInSet:set];

trimmedString就是過濾后的字符串

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

去除 username中的空格，table newline，nextline 
代碼如下：（三行代碼） 

NSCharacterSet *whitespace = [NSCharacterSet  whitespaceAndNewlineCharacterSet]; 

NSString * username = [mUsernameField  stringValue]; 

username = [username  stringByTrimmingCharactersInSet:whitespace]; 



注釋： 

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). 

另外可以用 whitespaceCharacterSet 替換 whitespaceAndNewlineCharacterSet 區(qū)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