Given a string, return a string where for every char in the original, there are two chars.

Sure! Here's a Python code snippet that doubles every character in a given string:

def double_char(string):
    doubled_string = ''
    for char in string:
        doubled_string += char * 2
    return doubled_string

You can call this function with a string as its argument and it will return a new string where each character in the original string is repeated twice. For example:

>>> double_char('hello')
'hheelllloo'
>>> double_char('1234')
'11223344'
>>> double_char('!')
'!!'

Let me know if you have any other questions!

相关问题

用java解决问题。 Given a string, return the sum of the digits 0-9 that appear in the string, ignoring all other characters. Return 0 if there are no digits in the string. (Note: Character.isDigit(char) tests if a char is one of the chars '0', '1', .. '9'. Integer.parseInt(string) converts a string to an int.)

可以使用Java中的正则表达式来实现该问题。具体实现步骤如下：

1.使用正则表达式匹配字符串中的所有数字，可以使用`\\d`表示数字。

2.将匹配到的数字字符串转换为整数类型并累加。

3.如果没有匹配到数字，则返回0。

下面是代码实现：

public int sumDigits(String str) {
    int sum = 0;
    Pattern pattern = Pattern.compile("\\d"); // 正则表达式，匹配数字
    Matcher matcher = pattern.matcher(str);
    while (matcher.find()) { // 查找匹配到的数字，并累加
        sum += Integer.parseInt(matcher.group());
    }
    return sum;
}

使用示例：

String str = "abc123def456";
int sum = sumDigits(str);
System.out.println(sum); // 输出 21，即 1+2+3+4+5+6

Given a string, return the length of the largest "block" in the string. A block is a run of adjacent chars that are the same.

Sure, I can help you with that. Here's a Python function that takes a string as input and returns the length of the largest block:

def largest_block(s):
    max_block_len = 0
    block_len = 1
    
    for i in range(1, len(s)):
        if s[i] == s[i-1]:
            block_len += 1
        else:
            max_block_len = max(max_block_len, block_len)
            block_len = 1
    
    return max(max_block_len, block_len)

Here's how you can use this function:

s = "abbcccdddd"
print(largest_block(s)) # Output: 4

In this example, the largest block in the string `s` is `"dddd"`, which has a length of 4.