題目(6kyu)：

Complete the solution so that it splits the string into pairs of two characters. If the >string contains an odd number of characters then it should replace the missing second >character of the final pair with an underscore ('_').

Examples:

• 'abc' => ['ab', 'c_']
• 'abcdef' => ['ab', 'cd', 'ef']

解題思路：

題目理解：將字串s分成每兩個字元一對，若字串s長度為奇數，則用＿來替換最後一組中缺少的字元。

def solution(s):
    """將字串每兩字元做拆分"""
    lst =[]
    if len(s)%2 == 1:
        s = s +"_"
    for x in range(0,len(s),2):
        lst.append(s[x:x+2])
    return lst