Find the Median Index in Python : Chris

Find the Median Index in Python
by: Chris
blow post content copied from  Finxter
click here to view original post

5/5 - (1 vote)

🐍 Question: How to find the index of the median element in a Python list? Something like argmedian()?

In case you need a quick refresher, I have written this tutorial on finding the median itself (but not yet its index):

👉 Recommended: 6 Ways to Get the Median of a Python List


A multi-liner solution to get the index of the median index is to first sort the list, take the mid-element from the sorted list, and search the index of the median using the list.index() method. This finds the index of the first occurrence of the median.

Here’s a code snippet that does that:

def median_index(lst):
    sorted_lst = sorted(lst)
    mid = len(lst) // 2
    median = sorted_lst[mid]
    return lst.index(median)

print(median_index([10, 1, 5]))
# 2

print(median_index([10, 1, 5, 99, 100, 100]))
# 3

print(median_index([10, 1, 5, 99, 100, 100, 0]))
# 0

This is a Python function that takes a list of numbers as input and returns the index of the median element of the list. Here’s how the code works:

  1. def median_index(lst): This line defines a function called median_index that takes a list lst as input.
  2. sorted_lst = sorted(lst): This line creates a new list called sorted_lst that contains the same elements as the input list lst, but sorted in ascending order using the built-in sorted() function.
  3. mid = len(lst) // 2: This line calculates the index of the median element in the original unsorted list lst by dividing the length of the list by 2 using the floor division operator //.
  4. median = sorted_lst[mid]: This line assigns the value of the median element in the sorted list sorted_lst to a new variable called median. If the length of the list is odd, this will be the element at the index mid. If the length of the list is even, mid will be the index of the element to the left of the middle two elements, and median will be the leftmost of those two elements.
  5. return lst.index(median): This line returns the index of the median element in the original unsorted list lst by using the built-in index() function to find the index of the first occurrence of the median value in lst.
  6. The print() statements at the end of the code call the median_index() function with different input lists and print the output to the console. For example, print(median_index([10, 1, 5])) will print 2 because the median element of the input list [10, 1, 5] is 5, and its index in the list is 2.

Python One-Liner to Find the Index of Median

I love Python one-liners. ♥

So, here’s the same code condensed in a single line of Python code that finds the index of the median element in the lst using lst.index(sorted(lst)[len(lst)//2])

def median_index(lst):
    return lst.index(sorted(lst)[len(lst)//2])

Python One-Liners Book: Master the Single Line First!

Python programmers will improve their computer science skills with these useful one-liners.

Python One-Liners

Python One-Liners will teach you how to read and write “one-liners”: concise statements of useful functionality packed into a single line of code. You’ll learn how to systematically unpack and understand any line of Python code, and write eloquent, powerfully compressed Python like an expert.

The book’s five chapters cover (1) tips and tricks, (2) regular expressions, (3) machine learning, (4) core data science topics, and (5) useful algorithms.

Detailed explanations of one-liners introduce key computer science concepts and boost your coding and analytical skills. You’ll learn about advanced Python features such as list comprehension, slicing, lambda functions, regular expressions, map and reduce functions, and slice assignments.

You’ll also learn how to:

  • Leverage data structures to solve real-world problems, like using Boolean indexing to find cities with above-average pollution
  • Use NumPy basics such as array, shape, axis, type, broadcasting, advanced indexing, slicing, sorting, searching, aggregating, and statistics
  • Calculate basic statistics of multidimensional data arrays and the K-Means algorithms for unsupervised learning
  • Create more advanced regular expressions using grouping and named groups, negative lookaheads, escaped characters, whitespaces, character sets (and negative characters sets), and greedy/nongreedy operators
  • Understand a wide range of computer science topics, including anagrams, palindromes, supersets, permutations, factorials, prime numbers, Fibonacci numbers, obfuscation, searching, and algorithmic sorting

By the end of the book, you’ll know how to write Python at its most refined, and create concise, beautiful pieces of “Python art” in merely a single line.

Get your Python One-Liners on Amazon!!

February 26, 2023 at 04:46AM
Click here for more details...

The original post is available in Finxter by Chris
this post has been published as it is through automation. Automation script brings all the top bloggers post under a single umbrella.
The purpose of this blog, Follow the top Salesforce bloggers and collect all blogs in a single place through automation.