- Trending Categories
- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies

- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who

# How to Find The Largest Or Smallest Items in Python?

This article is aimed at developers who want to find the largest or smallest items with Python. I will show a few methods touse and will conclude the best method for you.

## Method – 1: Slice approach on a List

If you are simply trying to find the single smallest or largest item i.e N = 1, it is faster to use min() and max().

Let us begin by generating some random integers.

import random # Create a random list of integers random_list = random.sample(range(1,10),9) random_list

## Output

[2, 4, 5, 1, 7, 9, 6, 8, 3]

## FINDING THE SMALLEST & LARGEST ITEM (N=1)

# Find the smallest number (N=1) min ( random_list )

## Output

1

# Find the largest number (N=1) max ( random_list )

## Output

9

## FINDING THE 3 SMALLEST & LARGEST ITEMS (N=3)

Similarly, if N is about the same size as the collection itself, it is usually faster to sort it first and take a slice of N.

# lets get the nsmallest using a slice approach(N=3) sorted(random_list)[:3]

## Output

[1, 2, 3]

# lets get the nlargest using a slice approach(N=3) sorted(random_list)[-3:]

## Output

[7, 8, 9]

## Method – 2: heapq Method on a List

The heapq module has two functions—nlargest() and nsmallest() that can be used to find the nsmallest or nlargest items.

import heapq import random random_list = random.sample(range(1,10),9) # nsmallest items (N=3) heapq.nsmallest(3,random_list)

## Output

[1, 2, 3]

# nlargest items (N=3) heapq.nlargest(3,random_list)

## Output

[9, 8, 7]

If you have a bit more complicated data, heapq functions have a key parameter that can be used.

import heapq grandslams = [ {'name':'Roger Federer','titles':20}, {'name:'Rafel Nadal','titles':19}, {'name':'Novak Djokovic','titles':17}, {'name':'Andy Murray','titles':3},] # Players with less titles (N=3) less = heapq.nsmallest(3,grandslams, key = lambdas:s['titles']) less

## Output

[{'name': 'Andy Murray', 'titles': 3}, {'name': 'Novak Djokovic', 'titles': 17}, {'name': 'Rafel Nadal', 'titles': 19}]

# Players with highest titles (N=3) more = heapq.nlargest(3,grandslams,key = lambdas:s['titles']) more

## Output

[{'name': 'Roger Federer', 'titles': 20}, {'name': 'Rafel Nadal', 'titles': 19}, {'name': 'Novak Djokovic', 'titles': 17}]

## Finding N Largest and Smallest from a DataFrame.

Well, the world is made up of CSV files, Yes they do!.

So it is very safe to assume that at some point in your python development you would encounter CSV’s and apparentlyDataFrame.

I will show you couple of methods to find the N largest/ smallest from a DataFrame.

In the first method we will sort the values using sort_values() method and pick up the values using head method.

import pandas as pd import io # Define your data data = """ player,titles Djokovic,17 Nadal,19 Federer,20 Murray,3 """ throwaway_storage = io.StringIO(data) df = pd.read_csv(throwaway_storage,index_col = "player")

# nsmallest (N = 3) df.sort_values("titles").head(3)

## Output

player title _______________ Murray 3 Djokovic 17 Nadal 19

# nlargest (N = 3) df.sort_values("titles",ascending = False).head(3)

## Output

player title _______________ Federer 20 Nadal 19 Djokovic 17

Instead of sorting the rows and using the .head() method, we can call the .nsmallest() and .nlargest() methods.

df.nsmallest(3,columns="titles")

## Output

player title _______________ Murray 3 Djokovic 17 Nadal 19

df.nlargest(3,columns = "titles")

## Output

player title _______________ Federer 20 Nadal 19 Djokovic 17

## Conclusion

If you are trying to find a relatively small number of items, then the nlargest() and nsmallest() functions are most appropriate.

If you are simply trying to find the single smallest or largest item (N=1), it is faster to use min() and max().

Similarly, if N is about the same size as the collection itself, it is usually faster to sort it first and take a slice.

In conclusion, the actual implementation of nlargest() and nsmallest() is adaptive in how python operates and will carry outsome of these optimizations on your behalf.

- Related Articles
- Python program to find Largest, Smallest, Second Largest, and Second Smallest in a List?
- C# program to find Largest, Smallest, Second Largest, Second Smallest in a List
- Java program to find Largest, Smallest, Second Largest, Second Smallest in an array
- Program to find largest product of three unique items in Python
- Python Program To Find the Smallest and Largest Elements in the Binary Search Tree
- How to find the rank of a vector elements in R from largest to smallest?
- Program to find minimum difference between largest and smallest value in three moves using Python
- C program to find the second largest and smallest numbers in an array
- Program to find Smallest and Largest Word in a String in C++
- Rearrange An Array In Order – Smallest, Largest, 2nd Smallest, 2nd Largest,. Using C++
- Program to find k-sized list where difference between largest and smallest item is minimum in Python
- How to find the smallest number greater than x in Python?
- Program to find the largest and smallest ASCII valued characters in a string in C++
- Find smallest and largest elements in singly linked list in C++
- Write a C program to find out the largest and smallest number in a series