pandas：减去两列并将结果保存为绝对值

Question

I have the code where I have a csv file opened in pandas and a new one I'm creating. There's a row I need to create "two last lines commented out" of an absolute value of subtracting two rows. I've tried a number of ideas in my head all bring an error.

import pandas as pd
import numpy as np

df = pd.read_csv(filename_read)
ids = df['id']

oosDF = pd.DataFrame()
oosDF['id'] = ids
oosDF['pred'] = pred
oosDF['y'] = df['target']
#oosDF['diff'] = oosdF['pred'] - oosDF['y']
#oosDF['diff'] = oosDF.abs()

Answer 1

I think you need for new DataFrame by subset (columns names in double [] ) and then get abs value of difference of columns:

oosDF = df[['id','pred', 'target']].replace(columns={'target':'y'})
oosDF['diff'] = (oosDF['pred'] - oosDF['y']).abs()

Answer 2

In your first commented line, you have oosdF instead of oosDF .

In your second commented line, you're setting the column to be abs() applied to the whole dataframe. That should be oosDF['diff'].abs()

Hope this helps!