Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Programming Articles
Page 352 of 2547
Python program to print Rows where all its Elements' frequency is greater than K
When working with nested lists (2D arrays), you may need to filter rows where every element appears more than K times within that row. Python provides an elegant solution using the all() function combined with list comprehension. Understanding the Problem We want to find rows where each element's frequency within that specific row exceeds a threshold value K. For example, in row [11, 11, 11, 11], the element 11 appears 4 times, so its frequency is 4. Solution Using Custom Function Here's a complete program that defines a helper function to check frequency conditions ? ...
Read MorePython Program to repeat elements at custom indices
When working with lists, you might need to repeat certain elements at specific positions. This can be achieved using Python's enumerate() function along with the extend() and append() methods to create a new list with duplicated elements at custom indices. Basic Approach Using enumerate() The most straightforward method is to iterate through the original list and check if the current index should have its element repeated ? original_list = [34, 56, 77, 23, 31, 29, 62, 99] print("The original list is:") print(original_list) indices_to_repeat = [3, 1, 4, 6] result = [] for index, element ...
Read MorePython – Inverse Dictionary Values List
Inverting a dictionary means swapping keys and values. When the original dictionary has lists as values, we create a new dictionary where each item in those lists becomes a key, and the original keys become the values. Using defaultdict The defaultdict from collections module automatically creates empty lists for new keys ? from collections import defaultdict my_dict = {13: [12, 23], 22: [31], 34: [21], 44: [52, 31]} print("The original dictionary is:") print(my_dict) inverted_dict = defaultdict(list) for key, values in my_dict.items(): for value in values: ...
Read MorePython – Sort String list by K character frequency
When it is required to sort a list of strings based on the K character frequency, the sorted() method and lambda function can be used. This technique counts how many times a specific character appears in each string and sorts accordingly. Syntax sorted(iterable, key=lambda string: -string.count(character)) Example Below is a demonstration of sorting strings by character frequency ? string_list = ['Hi', 'Will', 'Jack', 'Python', 'Bill', 'Mills', 'goodwill'] print("Original list:") print(string_list) K = 'l' print(f"Sorting by character '{K}' frequency:") # Sort by K character frequency (descending order) result = sorted(string_list, key=lambda ...
Read MorePandas GroupBy – Count the occurrences of each combination
When analyzing data, we often need to count how many times each combination of values appears across multiple columns. In Pandas, we can use DataFrame.groupby() with size() to count occurrences of each unique combination. Creating a Sample DataFrame Let's start by creating a DataFrame with car sales data ? import pandas as pd # Create sample data data = { 'Car': ['BMW', 'Mercedes', 'Lamborghini', 'Audi', 'Mercedes', 'Porsche', 'RollsRoyce', 'BMW'], 'Place': ['Delhi', 'Hyderabad', 'Chandigarh', 'Bangalore', 'Hyderabad', 'Mumbai', 'Mumbai', 'Delhi'], 'Sold': [95, 80, 80, ...
Read MorePython Program to extracts elements from a list with digits in increasing order
When it is required to extract elements from a list with digits in increasing order, a simple iteration, a flag value and the str method is used. This technique helps identify numbers where each digit is larger than the previous one. Example Let's extract numbers that have digits in strictly increasing order ? my_list = [4578, 7327, 113, 3467, 1858] print("The list is :") print(my_list) my_result = [] for element in my_list: my_flag = True for index in range(len(str(element)) - 1): ...
Read MorePython – Dual Tuple Alternate summation
When it is required to perform dual tuple alternate summation, a simple iteration and the modulus operator are used. This technique alternates between summing the first element of tuples at even indices and the second element of tuples at odd indices. Below is a demonstration of the same − Example my_list = [(24, 11), (45, 66), (53, 52), (77, 51), (31, 10)] print("The list is :") print(my_list) my_result = 0 for index in range(len(my_list)): if index % 2 == 0: my_result += ...
Read MorePython – Extract Rear K digits from Numbers
When it is required to extract rear K digits from numbers, a simple list comprehension, the modulo operator and the ** operator are used. The modulo operator with 10**K effectively extracts the last K digits from any number. How It Works The formula number % (10**K) extracts the rear K digits because: 10**K creates a number with K+1 digits (e.g., 10³ = 1000) The modulo operation returns the remainder when dividing by this value This remainder is always less than 10**K, giving us exactly the last K digits Example Let's extract the last ...
Read MorePython – Combine list with other list elements
When it is required to combine list with other list elements, Python provides several methods. The most common approaches are using iteration with append(), the extend() method, or the + operator. Method 1: Using Loop with append() This method iterates through the second list and appends each element to the first list ? my_list_1 = [12, 14, 25, 36, 15] print("The first list is :") print(my_list_1) my_list_2 = [23, 15, 47, 12, 25] print("The second list is :") print(my_list_2) for element in my_list_2: my_list_1.append(element) print("The result is :") print(my_list_1) ...
Read MorePython program to sort matrix based upon sum of rows
When it is required to sort a matrix based upon the sum of rows, we can use Python's built-in sort() method with a custom key function. The key function calculates the sum of each row, and the matrix is sorted in ascending order based on these sums. Method 1: Using a Custom Function Define a helper function that calculates the sum of a row and use it as the key for sorting ? def sort_sum(row): return sum(row) matrix = [[34, 51], [32, 15, 67], [12, 41], [54, 36, 22]] print("The ...
Read More