我该如何解决这个凌乱的 df？

编程问答 2022-08-11

问题描述

如何将这些凌乱的数据帧从字符串转换为底部建议的数据帧？

模块

import pandas as pad
import io

字符串数据

test = '\tStart\t \t \tStop\n\t12/12/20 1400\t\t\nrugby  \n\t12/16/20 1359\n\t12/12/20 1300\t\t\nsoccer \n\t12/19/20 0859\n\t12/12/20 1300\t\t\nbasketball \n\t12/19/20 0659\n\n\n\n'

变成熊猫数据框

test_raw = io.StringIO(test)
test_df = pad.read_csv(test,sep='\t')

test_df

    Unnamed: 0          Start       .1  Stop
0          NaN  12/12/20 1400 NaN  NaN   NaN
1      rugby              NaN NaN  NaN   NaN
2          NaN  12/16/20 1359 NaN  NaN   NaN
3          NaN  12/12/20 1300 NaN  NaN   NaN
4      soccer             NaN NaN  NaN   NaN
5          NaN  12/19/20 0859 NaN  NaN   NaN
6          NaN  12/12/20 1300 NaN  NaN   NaN
7  basketball             NaN NaN  NaN   NaN
8          NaN  12/19/20 0659 NaN  NaN   NaN

我如何把它变成：

           Start       Sport           Stop
0  12/12/20 1400       rugby  12/16/20 1359
1  12/12/20 1300      soccer  12/19/20 0859
2  12/12/20 1300  basketball  12/19/20 0659

提前谢谢@

解决方法

import re
import pandas as pd
import numpy as np

test = '\tStart\t \t \tStop\n\t12/12/20 1400\t\t\nrugby  \n\t12/16/20 1359\n\t12/12/20 1300\t\t\nsoccer \n\t12/19/20 0859\n\t12/12/20 1300\t\t\nbasketball \n\t12/19/20 0659\n\n\n\n'

# step1 split test by \n
alist = test.split('\n')

    # ['\tStart\t \t \tStop',#  '\t12/12/20 1400\t\t',#  'rugby  ',#  '\t12/16/20 1359',#  '\t12/12/20 1300\t\t',#  'soccer ',#  '\t12/19/20 0859',#  'basketball ',#  '\t12/19/20 0659',#  '',#  '']



# step2 we can see that every row has a location index rule
# 1. Start with index of 1,4,...,1+3n
# 2. Sport with index of 2,5,2+3n
# 3. Stop  with index of 3,6,3+3n

Start_col1 = alist[1::3] # -> ['\t12/12/20 1400\t\t','\t12/12/20 1300\t\t','','']
Sport_col2 = alist[2::3] # -> ['rugby  ','soccer ','basketball ','']
Stop_col3 = alist[3::3]  # -> ['\t12/16/20 1359','\t12/19/20 0859','\t12/19/20 0659','']

# step3 use zip to combine the same location index in a tuple
blist = list(zip(Start_col1,Sport_col2,Stop_col3))
# [('\t12/12/20 1400\t\t','rugby  ','\t12/16/20 1359'),#  ('\t12/12/20 1300\t\t','\t12/19/20 0859'),'\t12/19/20 0659'),#  ('','')]

# step4 convert to dataframe
dfn = pd.DataFrame(blist)
print(dfn)
#                     0            1                2
# 0  \t12/12/20 1400\t\t      rugby    \t12/16/20 1359
# 1  \t12/12/20 1300\t\t      soccer   \t12/19/20 0859
# 2  \t12/12/20 1300\t\t  basketball   \t12/19/20 0659
# 3                                                   

# step5 strip space 
dfn = dfn.applymap(str.strip)
print(dfn)

#                0           1              2
# 0  12/12/20 1400       rugby  12/16/20 1359
# 1  12/12/20 1300      soccer  12/19/20 0859
# 2  12/12/20 1300  basketball  12/19/20 0659
# 3                                          

# step6 delete null rows
cond = dfn[1] == ''
dfn = dfn[~cond]
print(dfn)

#                0           1              2
# 0  12/12/20 1400       rugby  12/16/20 1359
# 1  12/12/20 1300      soccer  12/19/20 0859
# 2  12/12/20 1300  basketball  12/19/20 0659

# step7 set columns of the DataFrame
dfn.columns = ['Start','Sport','Stop']
data-wranglingdataframepandas