python编程实现字符a-z和A-Z的字母串成的串，实 现每个字母由一个变成2个，再把每组字母 (如aa)切片装入列表List中。

python编程实现字符a-z和A-Z的字母串成的串，实 现每个字母由一个变成2个，再把每组字母 (如aa)切片装入列表List中。

lower = [chr(i) for i in range(ord('a'),ord('a')+26)]
upper = [chr(i) for i in range(ord('A'),ord('A')+26)]
letter = ''.join(lower+upper)
double = ''.join([s*2 for s in letter])
List = [s*2 for s in letter]

print(letter)
print(double)
print(List)

单步实现过程：

>>> lower = [chr(i) for i in range(ord('a'),ord('a')+26)]
>>> lower
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
>>> upper = [chr(i) for i in range(ord('A'),ord('A')+26)]
>>> upper
['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
>>> letter = ''.join(lower+upper)
>>> letter
'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
>>> double = ''.join([s*2 for s in letter])
>>> double
'aabbccddeeffgghhiijjkkllmmnnooppqqrrssttuuvvwwxxyyzzAABBCCDDEEFFGGHHIIJJKKLLMMNNOOPPQQRRSSTTUUVVWWXXYYZZ'
>>> List = [s*2 for s in letter]
>>> List
['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg', 'hh', 'ii', 'jj', 'kk', 'll', 'mm', 'nn', 'oo', 'pp', 'qq', 'rr', 'ss', 'tt', 'uu', 'vv', 'ww', 'xx', 'yy', 'zz', 'AA', 'BB', 'CC', 'DD', 'EE', 'FF', 'GG', 'HH', 'II', 'JJ', 'KK', 'LL', 'MM', 'NN', 'OO', 'PP', 'QQ', 'RR', 'SS', 'TT', 'UU', 'VV', 'WW', 'XX', 'YY', 'ZZ']

import string

res = [i * 2 for i in string.ascii_letters]
print(res)