Calculate the Median in Python

Your goal

You need to calculate the median of a numeric dataset in Python.

Step-by-step tutorial

The approach depends on whether you have list data or a Pandas DataFrame.

Approach 1: List data

For a Python list, you can use the statistics module from the Python Standard Library:

>>> import statistics
>>> statistics.median([3, 4, 4, 5, 10])
4

Approach 2: Pandas DataFrame

For a Pandas DataFrame, we can use its median method:

>>> import pandas as pd
>>> precip = pd.read_csv("precip-central-park.csv")
>>> precip
     YEAR   JAN   FEB   MAR   APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC  ANNUAL
0    1869  2.53  6.87  4.61  1.39  4.15  4.40  3.20  1.76  2.81  6.48  2.03  5.02   45.25
1    1870  4.41  2.83  3.33  5.11  1.83  2.82  3.76  3.07  2.52  4.97  2.42  2.18   39.25
2    1871  2.07  2.72  5.54  3.03  4.04  7.05  5.57  5.60  2.34  7.50  3.56  2.24   51.26
3    1872  1.88  1.29  3.74  2.29  2.68  2.93  7.83  6.29  2.95  3.35  4.08  3.18   42.49
4    1873  5.34  3.80  2.09  4.16  3.69  1.28  4.61  9.56  3.14  2.73  4.63  2.96   47.99
..    ...   ...   ...   ...   ...   ...   ...   ...   ...   ...   ...   ...   ...     ...
146  2015  5.23  2.04  4.72  2.08  1.86  4.79  3.98  2.35  3.28  3.91  2.01  4.72   40.97
147  2016  4.41  4.40  1.17  1.61  3.75  2.60  7.02  1.97  2.79  4.15  5.41  2.89   42.17
148  2017  4.83  2.48  5.25  3.84  6.38  4.76  4.19  3.34  2.00  4.18  1.58  2.21   45.04
149  2018  2.18  5.83  5.17  5.78  3.53  3.11  7.45  8.59  6.19  3.59  7.62  6.51   65.55
150  2019  3.58  3.14  3.87  4.55  6.82  5.46  5.77  3.70  0.95  6.15  1.95  7.09   53.03

[151 rows x 14 columns]
>>> precip.median()
YEAR      1944.00
JAN          3.20
FEB          3.05
MAR          3.71
APR          3.31
MAY          3.45
JUN          3.21
JUL          4.21
AUG          3.92
SEP          3.14
OCT          3.35
NOV          3.31
DEC          3.37
ANNUAL      44.55
dtype: float64

This produces the median of each DataFrame column.

We can also calculate the median for an individual DataFrame column, which is a Pandas Series:

>>> precip["ANNUAL"].median()
44.55