pandas isin function on a for loop

问题

1.csv

     cut  price  depth  carat  table
0   Good    327   57.9   0.23   65.0
1   Good    335   63.3   0.31   58.0
2 Very Good 336   62.8   0.24   57.0
3 Very Good 336   62.3   0.24   57.0
4 Very Good 337   61.9   0.26   55.0
5 Premium   326   59.8   0.21   61.0
6  Premium  334   62.4   0.29   58.0
7   Good    400   64.0   0.30   55.0

2.csv

     cut  price  depth  carat  table
0   Good    327   57.9   0.23   65.0
1   Good    335   63.3   0.31   58.0
2 Very Good 336   62.8   0.24   57.0
3 Very Good 336   62.3   0.24   57.0
4 Very Good 337   61.9   0.26   50.0
5 Premium   326   59.8   0.21   61.0
6  Premium  334   60.4   0.29   58.0
7   Good    399   64.0   0.30   55.0

only 4,6,7 rows from 2.csv is changed

i'm looking to get

output like this

     cut  price  depth  carat  table
4 Very Good 337   61.9   0.26   50.0
6  Premium  334   60.4   0.29   58.0
7   Good    399   64.0   0.30   55.0

can anyone share your experience any kind of help is fine

import pandas as pd
f1 = pd.read_csv('1.csv')
f2 = pd.read_csv('2.csv')
columns_list = ['cut', 'price', 'depth', 'carat', 'table']

new_df= f2[~f2.price.isin(f1.price)]
print(new_df)

this is a sample code i wrote and it's working fine but i need to use the

f2[~f2.price.isin(f1.price)]

in a loop to get each columns name on that 'price' space and also that will return the value.i tried in normal way like this

for i in columns_list:
price = f2[~f2.i.isin(f1.i)]
print(price)

but pandas command is not work with like this way it's return an error like

AttributeError: 'DataFrame' object has no attribute 'i'

Thankz for reading, i hope you understand this

回答1:

Use DataFrame.merge with indicator == True:

f2_filtered = (f2.merge(f1,how='outer',indicator=True)
                 .query('_merge == "left_only"')
                 .drop(columns = '_merge'))
print(f2_filtered)

Output

         cut  price  depth  carat  table
4  Very_Good    337   61.9   0.26   50.0
6    Premium    334   60.4   0.29   58.0
7       Good    399   64.0   0.30   55.0

来源：https://stackoverflow.com/questions/60975485/pandas-isin-function-on-a-for-loop