从pandas数据框中的每个单元格中删除列表 [英] Removing lists from each cell in pandas dataframe

问题描述

我有一个数据框，其中包含许多单个单元格中的列表.有些单元格没有列表，而只是字符串，而有些只是整数或数字.

I have one dataframe that contains lists in many of the individual cells. Some cells do not have lists and are just strings and some are just integers or numbers.

我想摆脱数据框中的所有列表(当然保留列表中的值或字符串).我该怎么办?

I would like to get rid of all lists in the dataframe (keeping the value or string that was in the list of course). How would I go about this?

下面是两个数据框，一个是原始数据"，其中始终包含列表，数字和字符串.第二个是我希望创建的干净数据.

Below are two dataframes, one is the "raw data" which has lists and numbers and strings throughout. The second is the clean data that I am hoping to create.

最简单，最有效的方法是什么?

What is the simplest and most efficient way to do this?

import pandas as pd

#create two dataframes, one called raw, one called end result
#raw data
raw_data = {'Name': [['W1'], ['W3'], ['W2'], ['W1'], ['W2'],['W3'],['G1']],
            'EVENT':['E1', 'E2', 'E3', 'E4', 'E5','E6','E1'],
        'DrillDate': [['01/01/2000'], 23, '04/01/2000', ['05/15/2000'], [''],[''],'02/02/2000']}
dfRaw = pd.DataFrame(raw_data, columns = ['Name','EVENT','DrillDate'])
dfRaw


# cleaned data
clean_data = {'Name': ['W1', 'W3', 'W2', 'W1', 'W2','W3','G1'],
            'EVENT':['E1', 'E2', 'E3', 'E4', 'E5','E6','E1'],
        'DrillDate': ['01/01/2000', 23, '04/01/2000', '05/15/2000', '','','02/02/2000']}
dfEndResult = pd.DataFrame(clean_data, columns = ['Name','EVENT','DrillDate'])
dfEndResult

推荐答案

使用applymap，并在单元格值上使用isinstance检查类型.

Using, applymap and check the type using isinstance on cell values.

In [666]: dfRaw.applymap(lambda x: x[0] if isinstance(x, list) else x)
Out[666]:
  Name EVENT   DrillDate
0   W1    E1  01/01/2000
1   W3    E2          23
2   W2    E3  04/01/2000
3   W1    E4  05/15/2000
4   W2    E5
5   W3    E6
6   G1    E1  02/02/2000

更新，如果您有空列表，并希望输出空白字符串.

Update, if you've empty lists and want blank string output.

In [689]: dfRaw.applymap(lambda x: x if not isinstance(x, list) else x[0] if len(x) else '')
Out[689]:
  Name EVENT   DrillDate
0   W1    E1  01/01/2000
1   W3    E2          23
2   W2    E3  04/01/2000
3   W1    E4  05/15/2000
4   W2    E5
5   W3    E6
6   G1    E1  02/02/2000

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