November 27, 2019

Calculating Column Statistics

Combine all values from a column for a single calculation.

The general syntax for these calculations is:
df.column_name.command()

Some common commands:
- nunique
- unique
- mean
- std
- median
- max
- min

Calculating Aggregate Functions

.groupby

grades = df.groupby(‘student’).grade.mean()
df.groupby(‘column1’).column2.measurement()

This creates a Series not a DataFrame.

If we use reset_index, it will be changed to a DataFrame from a Series.
measurement().reset_index()

We can rename columns using:
df = df.rename(columns = {“old” : “new”})