熊猫数据框中的字典列

Question

我有一个csv,我正在读一个熊猫数据帧.然而,其中一列是字典形式.这是一个例子:

ColA, ColB, ColC, ColdD
20, 30, {"ab":"1", "we":"2", "as":"3"},"String"

如何将其转换为如下所示的数据框:

ColA, ColB, AB, WE, AS, ColdD
20, 30, "1", "2", "3", "String"

编辑 我修复了问题,它看起来像这样但是是一个需要解析的字符串,而不是dict对象.

Answer 1

根据/sf/answers/2676215601/,您可以使用.apply(pd.Series)将包含dict的列映射到新列,然后将这些新列连接回原始数据帧减去原始dict包含列:

dw=pd.DataFrame( [[20, 30, {"ab":"1", "we":"2", "as":"3"},"String"]],
                columns=['ColA', 'ColB', 'ColC', 'ColdD'])
pd.concat([dw.drop(['ColC'], axis=1), dw['ColC'].apply(pd.Series)], axis=1)

返回:

ColA    ColB    ColdD   ab  as  we
20      30      String  1   3   2

Answer 2

所以从你的一行df开始

    Col A   Col B   Col C                           Col D
0   20      30      {u'we': 2, u'ab': 1, u'as': 3}  String1

编辑:根据OP的评论,我假设我们需要先转换字符串

import ast
df["ColC"] =  df["ColC"].map(lambda d : ast.literal_eval(d))

然后我们将Col C转换为dict,转置它然后将它连接到原始df

dfNew = df.join(pd.DataFrame(df["Col C"].to_dict()).T)
dfNew

这给了你这个

    Col A   Col B   Col C                           Col D   ab  as  we
0   20      30      {u'we': 2, u'ab': 1, u'as': 3}  String1 1   3   2

然后我们只需在dfNew中选择我们想要的列

dfNew[["Col A", "Col B", "ab", "we", "as", "Col D"]]

    Col A   Col B   ab  we  as  Col D
0   20      30      1   2   3   String1

Answer 3

怎么样：

import pandas as pd

# Create mock dataframe
df = pd.DataFrame([
    [20, 30, {'ab':1, 'we':2, 'as':3}, 'String1'],
    [21, 31, {'ab':4, 'we':5, 'as':6}, 'String2'],
    [22, 32, {'ab':7, 'we':8, 'as':9}, 'String2'],
], columns=['Col A', 'Col B', 'Col C', 'Col D'])

# Create dataframe where you'll store the dictionary values
ddf = pd.DataFrame(columns=['AB','WE','AS'])

# Populate ddf dataframe
for (i,r) in df.iterrows():
    e = r['Col C']
    ddf.loc[i] = [e['ab'], e['we'], e['as']]

# Replace df with the output of concat(df, ddf)
df = pd.concat([df, ddf], axis=1)

# New column order, also drops old Col C column
df = df[['Col A', 'Col B', 'AB', 'WE', 'AS', 'Col D']]

print(df)

输出：

   A 上校 B 上校 AB WE AS D 上校
0 20 30 1 2 3 字符串1
1 21 31 4 5 6 字符串2
2 22 32 7 8 9 字符串2