iOS NSString 字符串处理：截取字符串、匹配字符串、分隔字符串、拼接字符串、替换字符串

用到老是要去找，还是记下来方便！！！

1.截取字符串

NSString*string =@"tate_zwt";
string = [string substringToIndex:3];//截取下标7之后的字符串
WTLog(@"截取的值为：%@",string);

2.匹配字符串
NSString*string =@"tate_zwt";
NSRangerange = [stringrangeOfString:@"t"];//匹配得到的下标
WTLog(@"rang:%@",NSStringFromRange(range));
string = [string substringWithRange:range];//截取范围类的字符串
WTLog(@"截取的值为：%@",string);

3.分隔字符串
NSString*string =@"tate_zwt_zwt";
NSArray *array = [string componentsSeparatedByString:@"_"]; //从字符A中分隔成2个元素的数组
WTLog(@"array:%@",array); //结果是3个对象分别是：tate、zwt、zwt

4.拼接字符串

NSMutableString *append = [[NSMutableString alloc]init];

　[append appendString:@"我是"];

[append appendString:@"tate-zwt"];

WTLog(@"%@",append);//输出：我是tate-zwt

5.替换字符串

NSString *content = @"我是  tate-zwt";

content = [content stringByReplacingOccurrencesOfString:@" " withString:@""];

WTLog(@"%@",content);//输出：我是tate-zwt