Python中的填充列表 [英] Pad list in Python

问题描述

用python打印时如何填充列表?

How can I pad a list when printed in python?

例如，我有以下列表:

mylist = ['foo', 'bar']

我想将此填充到带有逗号的四个索引中.我知道我可以执行以下操作以将其作为逗号和空格分隔的列表:

I want to print this padded to four indices, with commas. I know I can do the following to get it as a comma and space separated list:

', '.join(mylist)

但是我如何用'x'将其填充到四个索引，所以输出就像:

But how can I pad it to four indices with 'x's, so the output is like:

foo, bar, x, x

推荐答案

In [1]: l = ['foo', 'bar']

In [2]: ', '.join(l + ['x'] * (4 - len(l)))
Out[2]: 'foo, bar, x, x'

['x'] * (4 - len(l))会生成一个列表，其中包含填充所需的正确数量的'x'条目.

The ['x'] * (4 - len(l)) produces a list comprising the correct number of 'x'entries needed for the padding.

编辑有人质疑len(l) > 4会发生什么.在这种情况下，['x'] * (4 - len(l)) 结果为空列表，预期的.

edit There's been a question about what happens if len(l) > 4. In this case ['x'] * (4 - len(l)) results in an empty list, as expected.

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