NSCharacterSet使用

（一）NSCharacterSet作用：

  对字符串进行上做过滤、删除或者分割操作

+ (NSCharacterSet *)controlCharacterSet;  //控制符
+ (NSCharacterSet *)whitespaceCharacterSet; //空格
+ (NSCharacterSet *)whitespaceAndNewlineCharacterSet; //空格和换行
+ (NSCharacterSet *)decimalDigitCharacterSet; //小数
+ (NSCharacterSet *)letterCharacterSet; //文字 
+ (NSCharacterSet *)lowercaseLetterCharacterSet; //字母数字
+ (NSCharacterSet *)uppercaseLetterCharacterSet; //可分解
+ (NSCharacterSet *)nonBaseCharacterSet; 
+ (NSCharacterSet *)alphanumericCharacterSet; //字母数字
+ (NSCharacterSet *)decomposableCharacterSet;
+ (NSCharacterSet *)illegalCharacterSet; //非法
+ (NSCharacterSet *)punctuationCharacterSet; //标点符号
+ (NSCharacterSet *)capitalizedLetterCharacterSet; //大写
+ (NSCharacterSet *)symbolCharacterSet; //符号
+ (NSCharacterSet *)newlineCharacterSet NS_AVAILABLE(10_5, 2_0); //换行符

（二）NSCharacterSet简单使用:(只会操作字符串的首尾)

NSString *testString = @"  .^this is just a test @";

/*去除字符串中的空格和换行*/
testString = [testString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

/*去除字符串中的标点*/
testString = [testString stringByTrimmingCharactersInSet:[NSCharacterSet punctuationCharacterSet]];

/*去除字符串中的符号*/
testString = [testString stringByTrimmingCharactersInSet:[NSCharacterSet symbolCharacterSet]];

NSLog(@"%@",testString);

结果输出:

    

* 如果想去除中间的，则把字符串分开进行操作:

NSString *string = @"  Lorem  * ipsum% dolar@  +sit  ^amet.  ";
    
//去除首位空格
string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
    
//以空格为分割符分成单词数组
NSArray *components = [string componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
NSMutableArray *newArr = [NSMutableArray array];
for (__strong NSString *subString in components) {
     //遍历数组，对每个单词进行处理
     subString = [subString stringByTrimmingCharactersInSet:[NSCharacterSet symbolCharacterSet]];
     subString = [subString stringByTrimmingCharactersInSet:[NSCharacterSet punctuationCharacterSet]];
     [newArr addObject:subString];
}
//重新以空格拼接还原字符串
 string = [newArr componentsJoinedByString:@" "];
NSLog(@"%@",string);

 结果输出:

Lorem   ipsum dolar  sit  amet