Python 比较 2 列并用第 3 列中的值写入第 4 列（熊猫）

Question

Python Compare 2 Columns And Write A 4th Column With Values From 3rd Column If Column 1 Matches Column 2. I have Two sheets in excel. First Sheet looks like sheet1 second sheets looks like Sheet2 .

I need to convert this formula into pandas formula. The formula which generate etype is

=IFERROR(INDEX(Sheet2!A:B,MATCH(Sheet1!A3,Sheet2!A:A,0),2),"herbs").

Answer 1

I think your question is still slightly confusing but I hope I am getting this correctly. Your idea is that you would like to compare a list of items that can either be fruit or herbs, and you have a list of fruits.

Using the list of fruits, you would like to then check it against your list of items to return the etype which should be a fruit if it matches any item in the list of fruits or herb otherwise.

If I am correct, you may refer to this suggested code below:

import pandas as pd

# Importing your data with pandas
main_df = pd.read_csv(filename, sheetname = 'Sheet1') # Sheet 1 should be all items
fruits_df = pd.read_csv(filename, sheetname = 'Sheet2') # fruits sheet

# Convert your fruits into a list since we know they are all fruits
fruit_lst = fruits_df['fruits'].tolist()

# Iterate through your main list of items and check if they are a fruit
for i in range(len(main_df)):
   # Update 'herb' -> 'fruit' if it matches
   if main_df['herbs'][i] in fruit_lst:
      main_df['etype'][i] = 'fruit'

Generating some samples from your screenshots, this is what the code should return.

Before, the dataframe would look something like this:

After the check against the fruit list, you should get the result you are looking for:

Hope this helps, though do try to share clearer details/screenshots in the future as well to help others understand your question!