Title: List Unique Values In A Pandas Column
Slug: pandas_list_unique_values_in_column
Summary: List Unique Values In A Pandas Column
Date: 2016-05-01 12:00
Category: Python
Tags: Data Wrangling
Authors: Chris Albon

Special thanks to Bob Haffner for pointing out a better way of doing it.

Preliminaries


In [1]:
# Import modules
import pandas as pd

# Set ipython's max row display
pd.set_option('display.max_row', 1000)

# Set iPython's max column width to 50
pd.set_option('display.max_columns', 50)

Create an example dataframe


In [2]:
# Create an example dataframe
data = {'name': ['Jason', 'Molly', 'Tina', 'Jake', 'Amy'], 
        'year': [2012, 2012, 2013, 2014, 2014], 
        'reports': [4, 24, 31, 2, 3]}
df = pd.DataFrame(data, index = ['Cochice', 'Pima', 'Santa Cruz', 'Maricopa', 'Yuma'])
df


Out[2]:
name reports year
Cochice Jason 4 2012
Pima Molly 24 2012
Santa Cruz Tina 31 2013
Maricopa Jake 2 2014
Yuma Amy 3 2014

List unique values


In [3]:
#List unique values in the df['name'] column
df.name.unique()


Out[3]:
array(['Jason', 'Molly', 'Tina', 'Jake', 'Amy'], dtype=object)