componentsSeparatedByString，componentsJoinedByString，componentsSeparatedByCharactersInSet

将string字符串转换为array数组

NSArray  *array = [Str componentsSeparatedByString:@","];

＝＝反向方法

将array数组转换为string字符串

NSString *tempString = [mutableArray componentsJoinedByString:@","];--分隔符

有字符串“A~B^C" ，我拆分为 "A", "B" 和 "C"?

NSString *str = @"A~B^C";

NSArray *arr = [str componentsSeparatedByCharactersInSet: [NSCharacterSet characterSetWithCharactersInString:@"^~"]];
NSLog(@"%@", arr);

／／字符

[NSCharacterSet whitespaceCharacterSet]