pandas :将长度不等的列表列拆分为多列 [英] Pandas: split column of lists of unequal length into multiple columns

问题描述

我有一个如下所示的Pandas数据框:

I have a Pandas dataframe that looks like the below:

                   codes
1                  [71020]
2                  [77085]
3                  [36415]
4                  [99213, 99287]
5                  [99233, 99233, 99233]

我正在尝试将df['codes']中的列表分成几列，如下所示:

I'm trying to split the lists in df['codes'] into columns, like the below:

                   code_1      code_2      code_3   
1                  71020
2                  77085
3                  36415
4                  99213       99287
5                  99233       99233       99233

其中没有值的列(因为列表没有那么长)用空白或NaN或其他内容填充.

where columns that don't have a value (because the list was not that long) are filled with blanks or NaNs or something.

我已经看到诸如这个问题这样的答案，并且其他类似的方法，当它们在等长列表上工作时，当我尝试在等长列表上使用这些方法时，它们都会抛出错误.有什么好方法吗?

I've seen answers like this one and others similar to it, and while they work on lists of equal length, they all throw errors when I try to use the methods on lists of unequal length. Is there a good way do to this?

推荐答案

尝试:

pd.DataFrame(df.codes.values.tolist()).add_prefix('code_')

   code_0   code_1   code_2
0   71020      NaN      NaN
1   77085      NaN      NaN
2   36415      NaN      NaN
3   99213  99287.0      NaN
4   99233  99233.0  99233.0

---

包含index

pd.DataFrame(df.codes.values.tolist(), df.index).add_prefix('code_')

   code_0   code_1   code_2
1   71020      NaN      NaN
2   77085      NaN      NaN
3   36415      NaN      NaN
4   99213  99287.0      NaN
5   99233  99233.0  99233.0

---

我们可以通过以下方式确定所有格式:

---

We can nail down all the formatting with this:

f = lambda x: 'code_{}'.format(x + 1)
pd.DataFrame(
    df.codes.values.tolist(),
    df.index, dtype=object
).fillna('').rename(columns=f)

   code_1 code_2 code_3
1   71020              
2   77085              
3   36415              
4   99213  99287       
5   99233  99233  99233

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