字符串 截取 替换

1.比如说有这样一个 字符串

    NSString * str = @"2017-05-06";

2.用数组存储分割的字符串（分割）

   NSArray *timeArray = [str componentsSeparatedByString:@"-"];

3.要得到  2017-5-6 的时间数据（替换）

    NSMutableString *a = [[NSMutableString  alloc] initWithString:timeArray[1]];
    NSRange range1 = NSMakeRange(0, 1);
    NSString *result1 = [a substringWithRange:range1];
    if ([result1 isEqualToString:@"0"]) {
        [a replaceCharactersInRange:NSMakeRange(0, 1) withString:@""];
    }
    NSMutableString *b = [[NSMutableString  alloc] initWithString:timeArray[2]];
    NSRange range = NSMakeRange(0, 1);
    NSString *result = [b substringWithRange:range];
    if ([result isEqualToString:@"0"]) {
        [b replaceCharactersInRange:NSMakeRange(0, 1) withString:@""];
    }
    NSString * timeStr = [NSString stringWithFormat:@"%@-%@-%@", _timeArray[0], a, b];