如何重复一个字符串直到另一个字符串的长度，包括空格？

Question

例如，

string1 = "The earth is dying"`
string2:"trees" 

我想要一个新字符串：tre estre es trees

我正在考虑将第一个字符串拆分为一个列表并进行迭代，但我无法获得第二个 for 循环，该循环将迭代第二个字符串并将其添加到第一个字符串，直到达到正确的长度？另外，我会有某种类型的 if 语句来检查空格并将它们添加到最终列表中。然后可能加入最终名单？

final_string = ''
string1_list = list(string1)
for i in range(string1_list):
    if string1_list[i] != " " #aka has a letter there
        for j in range(...) # how do I get a loop that would go through string2
        final_string += ... # and add into this string 

Answer 1

string1 = "The earth is dying"
string2 = "trees" 
result = ""
index = 0
for character in string1:
    if character == " ":
        result += " "
    else:
        result += string2[index%len(string2)]
        index+=1
print(result)

输出："tre estre es trees"

Answer 2

用itertools.cycle魔法：

from itertools import cycle

s1 = "The earth is dying"
s2 = "trees"

gen = cycle(s2)
res = ''.join(c if c.isspace() else next(gen) for c in s1)
print(res)

输出：

tre estre es trees