Adding value labels on a Matplotlib Bar Chart

Python – Create nested list containing values as the count of list items

Last Updated : 06 Feb, 2023

Given a list, the task is to write a Python program to create a nested list where the values are the count of list items.

Examples:

Input: [1, 2, 3]
Output: [[1], [2, 2], [3, 3, 3]]

Input: [4, 5]
Output: [[1, 1, 1, 1], [2, 2, 2, 2, 2]]

Method 1: Using nested list comprehension

The list will contain the count of the list items for each element e in the list we will create a list in the list with size e, in each list we will append the element e for e times.

Python3

l = [1, 2, 3, 4, 5]
l = [[i+1 for j in range(l[i])] for i in range(len(l))]
print(l)

Output:

[[1], [2, 2], [3, 3, 3], [4, 4, 4, 4], [5, 5, 5, 5, 5]]

Time Complexity : O(N^2)

Space Complexity : O(N^2)

Method 2:

The list will contain the count of the list items iterate the for loop for L times i.e. length of the list. Now at each element append a list, The appended list will be of the size count.

Python3

l = [1, 2, 3, 4, 5]
 
for i in range(len(l)):
    l[i] = [i+1 for j in range(i+1)]
     
print(l)

Output:

[[1], [2, 2], [3, 3, 3], [4, 4, 4, 4], [5, 5, 5, 5, 5]]

Time Complexity : O(N^2)

Space Complexity : O(N)

Method 3: Using *

Python3

l = [1, 2, 3, 4, 5]
nl=[]
for i in range(0,len(l)):
    j=[i+1]
    nl.append(j*l[i])
print(nl)

Output

[[1], [2, 2], [3, 3, 3], [4, 4, 4, 4], [5, 5, 5, 5, 5]]

Time Complexity : O(N^2)

Space Complexity : O(N)

Adding value labels on a Matplotlib Bar Chart

P

pulamolusaimohan

Improve

Article Tags :

Practice Tags :

python

Similar Reads

Python - Convert Key-Value list Dictionary to List of Lists

We are given a key value list dictionary we need to convert it list of lists. For example we are given a dictionary a = {'name': 'Geeks', 'age': 8, 'city': 'Noida'} we need to convert this into list of lists so the output should be [['name', 'Geeks'], ['age', 25], ['city', 'Geeks']]. Using List Comp

Count the Sublists Containing given Element in a List - Python

Given a list of lists our task is to count the number of sublists containing the given element x. For example: li = [[1, 3, 5], [1, 3, 5, 7], [1, 3, 5, 7, 9]] and x = 1 then output will be 3. Using List ComprehensionThis method uses list comprehension to check for the presence of the given element i

Convert a List of Lists into Tree-like Dict - Python

We are given a list of lists we need to convert it into tree-like dictionary. For example we are given a list of list li = [["a", "b", "c"], ["a", "b", "d"], ["x", "y"]] we need to convert it into tree like dict so that the output should be like {'a': {'b': {'c': {}, 'd': {}}}, 'x': {'y': {}}} .We c

Counting number of unique values in a Python list

Counting the number of unique values in a Python list involves determining how many distinct elements are present disregarding duplicates. Using a SetUsing a set to count the number of unique values in a Python list leverages the property of sets where each element is stored only once. [GFGTABS] Pyt

Counting the Frequencies in a List Using Dictionary in Python

Counting the frequencies of items in a list using a dictionary in Python can be done in several ways. For beginners, manually using a basic dictionary is a good starting point. Using Manual MethodIt uses a basic dictionary to store the counts, and the logic checks whether the item is already in the

Python - Convert a list into tuple of lists

When working with data structures in Python, there are times when we need to convert a list into a tuple of smaller lists. For example, given a list [1, 2, 3, 4, 5, 6], we may want to split it into a tuple of two lists like ([1, 2, 3], [4, 5, 6]). We will explore different methods to achieve this co

Python - Convert list of dictionaries to Dictionary Value list

We are given a list of dictionaries we need to convert it to dictionary. For example, given a list of dictionaries: d = [{'a': 1, 'b': 2}, {'a': 3, 'b': 4}, {'a': 5, 'b': 6}], the output should be: {'a': [1, 3, 5], 'b': [2, 4, 6]}. Using Dictionary ComprehensionUsing dictionary comprehension, we can

Convert List of Tuples to Dictionary Value Lists - Python

The task is to convert a list of tuples into a dictionary where the first element of each tuple serves as the key and the second element becomes the value. If a key appears multiple times in the list, its values should be grouped together in a list. For example, given the list li = [(1, 'gfg'), (1,

Python | Pair and combine nested list to tuple list

Sometimes we need to convert between the data types, primarily due to the reason of feeding them to some function or output. This article solves a very particular problem of pairing like indices in list of lists and then construction of list of tuples of those pairs. Let's discuss how to achieve the

Python - Convert List of Dictionaries to List of Lists

We are given list of dictionaries we need to convert it to list of lists. For example we are given a list of dictionaries a = [{'name': 'Geeks', 'age': 25}, {'name': 'Geeks', 'age': 30}] we need to convert it in list of list so that the output becomes[['Geeks',25],['Geeks;'30]]. Using List Comprehen