使用python将单元格数据拆分为多行

Question

我想使用 python 将单元格中包含的数据拆分为多行。下面给出了这样的一个例子：

这是我的数据：

fuel          cert_region   veh_class   air_pollution      city_mpg     hwy_mpg    cmb_mpg  smartway
ethanol/gas    FC              SUV          6/8              9/14        15/20      1/16      yes
ethanol/gas    FC              SUV          6/3              1/14        14/19      10/16     no

我想把它转换成这种形式：

fuel          cert_region   veh_class   air_pollution     city_mpg     hwy_mpg    cmb_mpg   smartway
ethanol         FC             SUV          6               9           15          1          yes
 gas            FC             SUV          8               14          20          16         yes
ethanol         FC             SUV          6               1           14          10         no  
 gas            FC             SUV          3               14          19          16         no

以下代码返回错误：

import numpy as np
from itertools import chain

# return list from series of comma-separated strings
def chainer(s):
return list(chain.from_iterable(s.str.split('/')))

# calculate lengths of splits
lens = df_08['fuel'].str.split('/').map(len)

# create new dataframe, repeating or chaining as appropriate
res = pd.DataFrame({
                'cert_region': np.repeat(df_08['cert_region'], lens),
                'veh_class': np.repeat(df_08['veh_class'], lens),
                'smartway': np.repeat(df_08['smartway'], lens),
                'fuel': chainer(df_08['fuel']),
                'air_pollution': chainer(df_08['air_pollution']),
                'city_mpg': chainer(df_08['city_mpg']),
               'hwy_mpg': chainer(df_08['hwy_mpg']),
               'cmb_mpg': chainer(df_08['cmb_mpg'])})

它给了我这个错误：

 TypeError                                 Traceback (most recent call last)
 <ipython-input-31-916fed75eee2> in <module>()
 20                     'fuel': chainer(df_08['fuel']),
 21                     'air_pollution_score': chainer(df_08['air_pollution_score']),
 ---> 22                     'city_mpg': chainer(df_08['city_mpg']),
 23                    'hwy_mpg': chainer(df_08['hwy_mpg']),
 24                    'cmb_mpg': chainer(df_08['cmb_mpg']),

  <ipython-input-31-916fed75eee2> in chainer(s)
  4 # return list from series of comma-separated strings
  5 def chainer(s):
  ----> 6     return list(chain.from_iterable(s.str.split('/')))
  7 
  8 # calculate lengths of splits

  TypeError: 'float' object is not iterable

但city_mpg具有Object数据类型：

   <class 'pandas.core.frame.DataFrame'>
   RangeIndex: 2404 entries, 0 to 2403
   Data columns (total 14 columns):
  fuel                    2404 non-null object
  cert_region             2404 non-null object
  veh_class               2404 non-null object
  air_pollution           2404 non-null object
  city_mpg                2205 non-null object
  hwy_mpg                 2205 non-null object
  cmb_mpg                 2205 non-null object
  smartway                2404 non-null object

Answer 1

我认为你最好构建一个新的数据框

result = pd.DataFrame(columns=[your_columns])
for index, series in df_08.iterrows():
    temp1 = {}
    temp2 = {}
    for key, value in dict(series).items():
        if '/' in value:
            val1, val2 = value.split('/')
            temp1[key] = [val1]
            temp2[key] = [val2]
        else:
            temp1[key] = temp2[key] = [value]

    result = pd.concat([result, pd.DataFrame(data=temp1), 
                        pd.DataFrame(data=temp2)], axis=0, ignore_index=True)