Python Pandas Dataframe Pulling cell value of Column B based on Column A

Question

struggling here. Probably missing something incredibly easy, but beating my head on my desk while trying to learn Python and realizing that's probably not going to solve this for me.

I have a dataframe df and need to pull the value of column B based on the value of column A.

Here's what I can tell you of my dataset that should make it easier. Column A is unique (FiscalYear) but despite being a year was converted to_numeric . Column B is not specifically unique (Sales) and like Column A was converted to to_numeric . This is what I have been trying as I was able to do this when finding the value of sales using idx max. However at a specific value, this is returning an error:

v = df.at[df.FiscalYear == 2007.0, 'Sales']

I am getting ValueError: At based indexing on an integer index can only have integer indexers I am certain that I am doing something wrong, but I can't quite put my finger on it.

And here's the code that is working for me.

v = df.at[df.FiscalYear.idxmax(), 'Sales']

No issues there, returning the proper value, etc.

Any help is appreciated. I saw a bunch of similar threads, but for some reason searching and blindly writing lines of code is failing me tonight.

Answer 1

you can use .loc method

df.Sales.loc[df.FiscalYear==2007.0]

this will be pandas series type object. if you want it in a list you can do:

df.Sales.loc[df.FiscalYear==2007.0].tolist()

Answer 2

你可以尝试一下：

v = df.at[df.FiscalYear.eq(2007.0).index[0], 'Sales']