Medical Data Visualizer - problem solving

Python
1

Hi

I’ve had some problems with this project so i Googled for solution… and there’s a thing that I can’t understand :confused:

  df_cat = pd.DataFrame(
      df_cat.groupby(
          ['variable', 'value', 'cardio'])['value'].count()).rename(
          columns={'value': 'total'}).reset_index()

Inside the pd.DataFrame() we have some column names and also [‘value’].count()
I get why there is count(), but i can’t understend where the second ‘value’ series comes from.

With this hint I have (kind of…) finished job but it’s pointless as i don’t get where does the second ‘value’ comes from.

Anybody can help me?

2

You’ve probably used the “melt” method at some point before for this dataframe (as the exercise tips to do so).

The pandas melt method receives a list of columns from your dataframe which you wish to analyse and then returns a new dataframe with two new columns, one which is ‘variables’ where you can see the “value_vars” you passed for it, and ‘values’ which is the value for each of these variables you’re analyzing.

Try printing df_cat before this piece of code so you can have a better look, sorry for the poor explanation I’m horrible with these things.