如何在不使用正则表达式的情况下从列表中的字符串打印双字母

def print_double_letters(strings):
    for string in strings:
        for i in range(len(string)-1):
            if string[i].isalpha() and string[i+1].isalpha():
                print(string[i:i+2])

# 示例用法
strings = ["Hello", "World", "Cloud", "Computing"]
print_double_letters(strings)

He
el
ll
lo
Wo
or
rl
ld
Cl
lo
ou
ud
Co
om
mp
pu
ut
ti
in
ng