字符串截取

1.字符串的截取

- (NSString *)substringFromIndex:(NSUInteger)from;
- 从指定位置from开始(包括指定位置的字符)到尾部

    NSString *str = @"<head>小码哥</head>";
    str = [str substringFromIndex:7];
    NSLog(@"str = %@", str);

输出结果: 小码哥</head>

- (NSString *)substringToIndex:(NSUInteger)to;

　　从字符串的开头一直截取到指定的位置to，但不包括该位置的字符

    NSString *str = @"<head>小码哥</head>";
    str = [str substringToIndex:10];
    NSLog(@"str = %@", str);

输出结果: <head>小码哥

- (NSString *)substringWithRange:(NSRange)range;

　　按照所给出的NSRange从字符串中截取子串

    NSString *str = @"<head>小码哥</head>";
    NSRange range;
    /*
    range.location = 6;
    range.length = 3;
    */
    range.location = [str rangeOfString:@">"].location + 1;
    range.length = [str rangeOfString:@"</"].location - range.location;
    NSString *res = [str substringWithRange:range];
    NSLog(@"res = %@", res);
输出结果: 小码哥