Given a list of numbers, the task is to write a Python program to find the largest number in given list.
Examples:
Input : list1 = [10, 20, 4]
Output : 20
Find Largest Number in a List with Native Example
Sort the list in ascending order and print the last element in the list.
Python3
# Python program to find largest# number in a list# list of numberslist1 = [10, 20, 4, 45, 99]# sorting the listlist1.sort()# printing the last elementprint("Largest element is:", list1[-1]) |
Largest element is: 99
Time Complexity: O(nlogn)
Auxiliary Space: O(1)
Find Largest Number in a List Using max() method
Here list1 is a list with some element and we will use max() function, this will return maximum from the array.
Python3
# Python program to find largest# number in a list# List of numberslist1 = [10, 20, 4, 45, 99]# Printing the maximum elementprint("Largest element is:", max(list1)) |
Largest element is: 99
Time complexity : O(n)
Auxiliary Space : O(1)
Find the max list element on inputs provided by user
Python3
# Python program to find largest# number in a list# Creating an empty listlist1 = []# asking number of elements to put in listnum = int(input("Enter number of elements in list: "))# Iterating till num to append elements in listfor i in range(1, num + 1): ele = int(input("Enter elements: ")) list1.append(ele)# Printing maximum elementprint("Largest element is:", max(list1)) |
Output:
Enter number of elements in list: 4
Enter elements: 12
Enter elements: 19
Enter elements: 1
Enter elements: 99
Largest element is: 99
Time complexity : O(n)
Auxiliary Space : O(1)
Find Largest Number in a List Without using built-in functions
Python3
# Python program to find largest# number in a listdef myMax(list1): # Assume first number in list is largest # initially and assign it to variable "max" max = list1[0]# Now traverse through the list and compare # each number with "max" value. Whichever is # largest assign that value to "max'. for x in list1: if x > max: max = x # after complete traversing the list # return the "max" value return max# Driver codelist1 = [10, 20, 4, 45, 99]print("Largest element is:", myMax(list1)) |
Largest element is: 99
Time complexity : O(n)
Auxiliary Space : O(1)
Find Largest Number in a List Using the lambda function
Python lambda which is also know as inline function, here we will use max inside the lambda.
Python3
# python code to print largest element in the listlst = [20, 10, 20, 4, 100]print(max(lst, key=lambda value: int(value)) ) |
100
Time complexity : O(n)
Auxiliary Space: O(n), where n is the length of the list.
Find Largest Number in a List Using reduce function
Using reduce() function we will get the maximum element from the array.
Python3
from functools import reducelst = [20, 10, 20, 4, 100]largest_elem = reduce(max, lst)print(largest_elem) |
100
Time Complexity: O(n)
Auxiliary Space: O(1)
Find Largest Number in a List Using recursion
Python3
# Function to find the largest element in the listdef FindLargest(itr, ele, list1): # Base condition if itr == len(list1): print("Largest element in the list is: ", ele) return # Check max condition if ele < list1[itr]: ele = list1[itr] # Recursive solution FindLargest(itr+1, ele, list1) return # input listlist1 = [2, 1, 7, 9, 5, 4]FindLargest(0, list1[0], list1) |
Largest element in the list is: 9
Time Complexity: O(n)
Auxiliary Space: O(n)
Find Largest Number in a List Using heapq.nlargest()
Here’s how you can use heapq.nlargest() function to find the largest number in a list:
Algorithm:
- Import the heapq module.
- Create a list of numbers.
- Use the heapq.nlargest() function to find the largest element. The nlargest() function takes two arguments – the first argument is the number of largest elements to be returned, and the second argument is the list of numbers.
- Retrieve the largest element from the list of largest elements returned by heapq.nlargest() function.
- Print the largest element.
Python3
import heapq# list of numberslist1 = [10, 20, 4, 45, 99]# finding the largest element using heapq.nlargest()largest_element = heapq.nlargest(1, list1)[0]# printing the largest elementprint("Largest element is:", largest_element) |
Largest element is: 99
Time complexity: O(nlogk), where n is the length of the list and k is the number of largest elements to be returned. In this case, k is 1, so the time complexity is O(nlog1) = O(n).
Auxiliary Space: O(k), where k is the number of largest elements to be returned. In this case, k is 1, so the auxiliary space is O(1).
Find Largest Number in a List Using np.max() method
- Initialize the test list.
- Use np.array() method to convert the list to numpy array.
- Use np.max() method on numpy array which gives the max element in the list.
Python3
import numpy as np# given listlist1 = [2, 7, 5, 64, 14]# converting list to numpy arrayarr = np.array(list1)# finding largest numbers using np.max() methodnum = arr.max()# printing largest numberprint(num) |
Output:
64
Time Complexity: O(n) where n is the length of the list.
Auxiliary Space: O(n) where n is the length of the list. because numpy array of length n is created.
