{"id":901,"date":"2024-09-15T11:20:11","date_gmt":"2024-09-15T11:20:11","guid":{"rendered":"https:\/\/www.zframez.com\/articles\/?p=901"},"modified":"2024-10-16T15:52:29","modified_gmt":"2024-10-16T15:52:29","slug":"chapter-6-python-while-and-for-loops-examples-and-explanations","status":"publish","type":"post","link":"https:\/\/www.zframez.com\/articles\/python-tutorials\/chapter-6-python-while-and-for-loops-examples-and-explanations","title":{"rendered":"Chapter 6: Python While and For Loops: Examples and Explanations"},"content":{"rendered":"\n
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Python While and For Loops<\/strong><\/h1>\n\n\n\n

In this chapter of our Python tutorial series, we will explore two essential looping structures in Python: while loops and for loops. Loops are a fundamental part of programming, allowing you to execute a block of code repeatedly under specific conditions. In this chapter, you\u2019ll learn how to use while loops with the else<\/code> clause, how to control output formatting using Python\u2019s print()<\/code> function, and how to iterate over a range of numbers or lists with for loops. By the end of this chapter, you\u2019ll be able to write efficient loops in Python and apply them to various real-world scenarios.<\/p>\n\n\n\n

While Loop Examples in Python<\/strong> :<\/h2>\n\n\n\n
a = 5\nb = 1\n\nwhile b <= 5:\n    print (f\" {a} * {b} = {a * b})\n    b += 1<\/code><\/pre>\n\n\n\n
Output: <\/p>\n\n\n\n
5 * 1 = 5
5 * 2 = 10
5 * 3 = 15
5 * 4 = 20
5 * 5 = 25<\/pre>\n\n\n\n
Explanation<\/strong>:
In this example, the while loop in Python continues to run as long as the condition b <= 5<\/code> is true. It prints the multiplication table for a = 5<\/code> and increments b<\/code> after each iteration until b<\/code> exceeds 5.<\/p>\n\n\n\n
Using else<\/code> with While Loops in Python<\/strong><\/h2>\n\n\n\n
a = 1\n\nwhile a <= 3:\n    b = int(input(\"Enter a number: \"))\n    \n    if b == 0:\n        print(\"Exiting loop with break command, 'else' is not executed\")\n        break\n    a += 1\n    \nelse:\n    print(\"Loop exited without executing break command\")\n<\/code><\/pre>\n\n\n\n
Explanation<\/strong>:
In this Python example, the else<\/code> block is executed only if the while loop completes normally without encountering a break<\/code> statement. If the user enters 0<\/code>, the loop breaks, and the else<\/code> block is skipped.<\/p>\n\n\n\n
Using print<\/code> Without a Newline in Python<\/strong><\/h2>\n\n\n\n
a = 1\n\nwhile a < 10:\n    print(a, end=',')\n    a += 1<\/code><\/pre>\n\n\n\n
Output: <\/p>\n\n\n\n
1,2,3,4,5,6,7,8,9,<\/pre>\n\n\n\n
Explanation<\/strong>:
Here, the end=','<\/code> argument in the print()<\/code> function prevents the automatic newline after each printed value. Instead, the numbers are printed on the same line, separated by commas.<\/p>\n\n\n\n
Using the range()<\/code> Function in Python For Loops<\/strong><\/h2>\n\n\n\n
for a in range(10):\n    print(a, end=\" \")<\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
0 1 2 3 4 5 6 7 8 9<\/pre>\n\n\n\n
Explanation<\/strong>:
The range()<\/code> function in Python generates numbers from 0 to 9, and the for loop iterates through each number, printing them on the same line with spaces in between.<\/p>\n\n\n\n
Multiplication Table with For Loops<\/strong><\/h2>\n\n\n\n
a = 5\n\nfor b in range(1, 5):\n    print(f\" {a} * {b} = {a * b})\n<\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
5 * 1 = 5
5 * 2 = 10
5 * 3 = 15
5 * 4 = 20<\/pre>\n\n\n\n
Explanation<\/strong>:
This for loop prints the multiplication table for a = 5<\/code> for values of b<\/code> from 1 to 4, using Python\u2019s range()<\/code> function.<\/p>\n\n\n\n
For Loops with Lists in Python<\/strong><\/h2>\n\n\n\n
a = [10, 20, 30, 40, 50]\n\nfor b in a:\n    print(b + 5, end=\" \")\n<\/code><\/pre>\n\n\n\n
Output: <\/p>\n\n\n\n
15 25 35 45 55<\/pre>\n\n\n\n
Explanation<\/strong>:
In this Python example, a for loop iterates over a list of integers, adds 5 to each element, and prints the result.<\/p>\n\n\n\n
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Programming Exercises: <\/strong><\/h2>\n\n\n\n
    \n
  1. Write a Python program to print the square of all numbers from 0 to 10.<\/li>\n\n\n\n
  2. Write a Python program to find the sum of all even numbers from 0 to 10.<\/li>\n\n\n\n
  3. Write a Python program to read three numbers (a, b, c) and check how many numbers between \u2018a\u2019 and \u2018b\u2019 are divisible by \u2018c\u2019.<\/li>\n\n\n\n
  4. Write a Python program to print two columns of numbers, where the first column starts from 1 and increments to 99, while the second column starts from 99 and decrements to 1. Each line should display a pair of numbers in the following format: \n