The Python 21 Day Coding Challenge

Learn to write a program that reads two numbers and computes their sum. See examples like 3 and 4 yielding 7, and 2.5 and 1.8 yielding 4.3.

In Python, read two numbers from input, cast to int or float, sum them, and display the result as a string, handling integer versus float outputs.

Write a program that takes a number as input and checks if it is prime; examples show 7 prime, 12 not prime, 15 not prime, and 29 prime.

Check if n is prime by looping from two to the square root of n, marking as prime if no divisor exists, otherwise not prime (composite).

Learn to implement a factorial calculator in Python by writing a program that reads a number and outputs its factorial. See examples for 0, 3, 5, 7, and 10.

Implement factorial calculation in Python by multiplying 1 to n, starting with 1 (or 2 for efficiency), and verify with 5 yields 120 and 0! = 1.

Write a program that reads a triangle’s base and height and calculates its area, with samples like 5 and 8 producing 20.

Calculate the triangle area by inputting base and height as floats, applying 1/2 * base * height, and displaying whole numbers or decimals with prompts enter base and enter height.

Build a Celsius to Fahrenheit converter by coding accurate temperature conversion for inputs such as 0, 25, -10, 100, and 37, producing outputs 32, 77, 14, 212, and 98.6.

Learn to convert Celsius to Fahrenheit by applying the formula num * 9 / 5 + 32, using a num variable and handling integer results without trailing decimals.

Develop a program that generates the fibonacci sequence up to a given number and outputs the corresponding list, using examples for ten, twenty, five, one, and fifty.

Generate the Fibonacci sequence up to a given number by starting with 0 and 1, appending sums of the two previous numbers, and handling zero or negative inputs.

Write a program that checks if a string is a palindrome. Use examples such as level and racecar as true, hello and python as false.

Learn to implement a palindrome check in Python by comparing characters from both ends, using zero-based indexing, length calculations, and range with integer division for optimization.

Count occurrences of a specific character in a string by providing the two inputs: the string and the target character.

Learn to count occurrences of a specific character in a string by looping through each character, initializing a zero counter, and incrementing on matches, noting Python's case sensitivity.

Write a program that calculates the average of a given list of numbers, illustrated by examples yielding 3, 30, 6, 35, and 0.

Write a Python program to compute the average of a number list, parsing input with eval, converting elements to float, and guarding against empty lists to avoid division by zero.

Write a program that finds the largest element in a list of numbers and outputs the maximum for several example inputs.

Learn to find the largest element in a list of numbers by initializing with the first value, iterating to update on larger elements, and handling empty lists.

Tackle the problem of list sorting by writing a program that sorts a given list of numbers in ascending order. Explore examples that convert inputs like 3,1,4,2,5 into 1,2,3,4,5.

Sort a list of numbers in ascending order with a Python selection sort, converting input to a list, handling floats, and swapping elements to place the minimum at each step.

Practice string reversal by coding a program that reverses a given string without the built in reverse function, using examples like hello and world to show the output order.

Learn to reverse a string without the built-in reverse function by using a for loop to prepend each character to an empty result, then print the reversed string.

Practice anagram check by writing a program that takes two input strings and returns true if they are anagrams and false otherwise.

Learn to build a python anagram checker by sorting strings or using a boolean check array for characters, with practical tests like listen vs silent and empty strings.

Master how the Python 21 day coding challenge teaches you to write a program that calculates power from a base and an exponent, with examples two and three yielding eight.

Learn to compute powers in Python by reading base and exponent, converting inputs, and using the ** exponent operator with an iterative loop for integer exponents, e.g., 2**3 and 5**0.

Write a program to compute the length of the longest word in a sentence, demonstrated with examples like I love programming and OpenAI is revolutionizing artificial intelligence.

Demonstrates writing a program to find the length of the longest word in a sentence by counting letter-only words, handling endings and edge cases with tests.

Develop a recursive factorial calculator by writing a program that computes the factorial of a given number, with examples for five, three, seven, one, and ten.

Implement a recursive factorial in Python by defining a factorial function with a base case of zero equals one, validating integer input, and handling invalid cases.

Remove duplicates from a list while preserving the original order of first appearances. Learn to implement this in Python to output a clean list of unique numbers.

Learn how to remove duplicates from a list in Python by iterating through elements, checking if an element is not in the result, appending it, and printing the final list.

Write a program to check if a given number is a perfect square, demonstrated with true for 16, true for 25, false for 10 and 14, and true for 9.

Learn to code a Python check for a perfect square using a square root comparison and an alternative integer loop without square root, handling zero and negative inputs.

Learn to convert decimal numbers to binary in python through a practical exercise, with examples: 27 → 11011, 5 → 101, 15 → 10000, 35 → 100011.

Explore decimal to binary conversion by repeatedly dividing by two, collecting remainders, and prefixing digits to build the binary string, with handling for zero (and notes on negatives).

Tackle the sum of even numbers in a list in the Python 21 day coding challenge by writing a program that adds all even values and returns the total.

Learn to sum all even numbers in a list using Python. Convert input to a list, then iterate elements, check evenness with mod 2, and accumulate the result.

Learn to find the middle element(s) of a list in Python, returning a list with one middle item for odd lengths and two for even lengths.

solve middle elements of a list without sorting using zero-based indexing. odd lists yield one result, even lists yield two, illustrated with five and six element cases in python.