Creating a Pandas dataframe from elements of a dictionary

Question

I'm trying to create a pandas dataframe from a dictionary. The dictionary is set up as

nvalues = {"y1": [1, 2, 3, 4], "y2": [5, 6, 7, 8], "y3": [a, b, c, d]}

I would like the dataframe to include only "y1" and "y2". So far I can accomplish this using

df = pd.DataFrame.from_dict(nvalues)
df.drop("y3", axis=1, inplace=True)

I would like to know if it is possible to accomplish this without having df.drop()

Answer 1

You can specify columns in the DataFrame constructor:

pd.DataFrame(nvalues, columns=('y1', 'y2'))

   y1  y2
0   1   5
1   2   6
2   3   7
3   4   8

Answer 2

You could use a dictionary comprehension to filter out unwanted keys like so:

df = pd.DataFrame.from_dict({k: v for k, v in nvalues.items() if k != 'y3'})

to get:

   y1  y2
0   1   5
1   2   6
2   3   7
3   4   8

There are of course quite a few ways to remove one or more keys from a dictionary.