像excel列一样重复字母? [英] Repeating letters like excel columns?

问题描述

我想创建一个类似于 Microsoft Excel 中列字母的字符串列表.比如26列之后，接下来的列变成AA、AB、AC等

我曾尝试使用模数运算符，但我最终得到了 AA、BB、CC 等...

导入字符串pass_through_alphabet = 0对于 num, col in enumerate([_ for _ in range(40)]):如果数量 % 26 == 0:pass_through_alphabet += 1excel_col = string.ascii_uppercase[num%26] * pass_through_alphabet打印(数字，excel_col)0 安1 乙2 C3D...22 瓦23 X24岁25 Z26 AA27 BB28 CC...

解决方案

您可以使用 itertools.product 用于此:

<预><代码>>>>导入迭代工具>>>列表(itertools.product(string.ascii_uppercase，repeat=2))[('A', 'A'), ('A', 'B'), ('A', 'C'), ('A', 'D'), ...

将其与第一组字母组合，并加入对的结果:

<预><代码>>>>列表(... itertools.chain(... string.ascii_uppercase，... (''.join(pair) for pair in itertools.product(string.ascii_uppercase, repeat=2))...))['A', 'B', 'C', .. 'AA', 'AB', 'AC' .. 'ZZ']

概括地说，我们定义了一个生成越来越大的产品的生成器.请注意，yield from 仅在 python 3.3+ 中可用，但如果您使用的是 python 2，则可以使用 for 循环来生成每个项目.

 >>>def excel_cols():...:n = 1...:而真:...: yield from (''.join(group) for group in itertools.product(string.ascii_uppercase, repeat=n))...:n += 1>>>列表(itertools.islice(excel_cols()，28))['一种'，'乙','C'，...'X'，'你','Z','AA','AB']

I want to create a list of string that resemble the column letters in Microsoft Excel. For example, after 26 columns, the next columns become AA, AB, AC, etc.

I have tried using the modulus operator, but I just end up with AA, BB, CC, etc...

import string

passes_through_alphabet = 0

for num, col in enumerate([_ for _ in range(40)]):
    if num % 26 == 0:
        passes_through_alphabet += 1
    excel_col = string.ascii_uppercase[num%26] * passes_through_alphabet
    print(num, excel_col)

0 A
1 B
2 C
3 D
...
22 W
23 X
24 Y
25 Z
26 AA
27 BB
28 CC
...

解决方案

You can use itertools.product for this:

>>> import itertools
>>> list(itertools.product(string.ascii_uppercase, repeat=2))
[('A', 'A'), ('A', 'B'), ('A', 'C'), ('A', 'D'), ...

Combining this with the first set of letters, and joining the pairs results in:

>>> list(
...     itertools.chain(
...         string.ascii_uppercase, 
...        (''.join(pair) for pair in itertools.product(string.ascii_uppercase, repeat=2))
... ))
['A', 'B', 'C', .. 'AA', 'AB', 'AC' .. 'ZZ']

To generalise, we define a generator which builds up bigger and bigger products. Note that the yield from is only available in python 3.3+, but you can just use a for loop to yield each item if you're on python 2.

 >>> def excel_cols():
...:     n = 1
...:     while True:
...:         yield from (''.join(group) for group in itertools.product(string.ascii_uppercase, repeat=n))
...:         n += 1

>>> list(itertools.islice(excel_cols(), 28))
['A',
 'B',
 'C',
 ...
 'X',
 'Y',
 'Z',
 'AA',
 'AB']

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