如何比较 Python 中两个数据框中的两列值？

Question

I have two dataframes and I have created a "Check" column in second dataframe to check if values in the Total Claims columns are equal. Here are my two dataframes:

Dataframe 1

Dataframe 2

The code that I used to create the "Check" column comparing Total Claims between the two dataframes was:

reported_claims['Check'] =  np.where(reported_claims['Total Claims'].reset_index(drop=True) == df['Total Claims'].reset_index(drop=True) , 'TRUE', 'FALSE')

I noticed that the 7th values in two dataframes are both 31.32 but the check columns says False. I was just wondering why is it saying False and how would I fix this problem? Thank you so much for your time!

Answer 1

The issue arises by comparing two floating point numbers. The general rule for most programming languages (including python) is that you can never check if two floats are exactly equal . You have to instead check if the two values are close. You can do so using the np.isclose() . Check this answer for a reference on how to use it.

Answer 2

Use merge command to join two dataframe and add check column to compare two columns

df = pd.merge(left=Dataframe1, right=Dataframe2, left_on='month', right_on='month')