# Python - How To Find Median of a List in Python

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In the world of statistics and probability, the median value of a given set of observations is the middle element. It is calculated differently when the total number of elements is odd and even.

Python is frequently used for data and statistical analysis. This tutorial will introduce how to calculate the median of a list in Python.

## Use the `statistics` Module to Find the Median of a List in Python

In Python, we have the `statistics` module with different functions and classes to find different statistical values from a set of data. The `median()` function from this library can be used to find the median of a list.

Since the median is founded on a sorted list of data, the `median()` function automatically sorts it and returns the median. For example,

``import statistics  lst = [7,8,9,5,1,2,2,3,4,5]  print(statistics.median(lst)) ``

Output:

``4.5 ``

## Use the `numpy.percentile` Function to Find the Median of a List in Python

In the `NumPy` module, we have functions that can find the percentile value from an array. The median of data is the 50th percentile value. To find this, we can use the `percentile()` function from the `NumPy` module and calculate the 50th percentile value. See the following code.

``import numpy as np  a = np.array([7,8,9,5,1,2,2,3,4,5] ) median_value = np.percentile(a, 50)  print(median_value)  ``

Output:

``4.5 ``

## Use the Custom Code to Find the Median of a List in Python

We can also apply the formula to find the median of data using Python and create our user-defined function. For example,

``lst = [7,8,9,5,1,2,2,3,4,5]   def median(l):     half = len(l) // 2     l.sort()     if not len(l) % 2:         return (l[half - 1] + l[half]) / 2.0     return l[half]  print(median(lst)) ``

Output:

``4.5 ``

The median of a list is the middle element of the sorted list if the list’s length is odd; otherwise, it is the average of the two middle elements.