去除 username中的空格，table newline，nextline

代码如下：（三行代码）

NSCharacterSet *whitespace = [NSCharacterSet  whitespaceAndNewlineCharacterSet];

NSString * username = [mUsernameField  stringValue];

示例

username = [username  stringByTrimmingCharactersInSet:whitespace];

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行是去除回车

//自定义想要去除的字符

在iOS中 ��可以使用stringByTrimmingCharactersInSet函数过滤字符串中的特殊符号

首先自己定义一个NSCharacterSet, 包含需要去除的特殊符号

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

由于NSString中有全角符号和半角符号, 因此有些符号要包括全角和半角的

然后调用stringByTrimmingCharactersInSet

NSString *trimmedString = [string stringByTrimmingCharactersInSet:set];

trimmedString就是过滤后的字符串

\注释

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 替换 whitespaceAndNewlineCharacterSet 区别newline nextline

whitespaceCharacterSet

Returns a character set containing only the in-line whitespace characters space (U+0020) and tab (U+0009).