for loop for multiplication tables

Okay, let’s create a multiplication table using a for loop! ✨ This is a perfect example to show how a for loop helps automate tasks we’d otherwise have to repeat manually.

Imagine you want to print the multiplication table for a number, say 5. You’d normally do this:

• 5 times 1 equals 5
• 5 times 2 equals 10
• …
• 5 times 10 equals 50

Writing all those lines manually would be tedious! 😩 But with a for loop, we can tell the computer: “For each number from 1 to 10, calculate and print the result of multiplying our number by that number.”

Here’s why a for loop is a great choice for this task: we know exactly how many times we need to repeat the multiplication – 10 times (for multiplying by 1 through 10). When the number of iterations is known, the for loop is generally more suitable than a while loop.

We’ll use the range() function again! 🔢 Remember, range() generates a sequence of numbers.

Here’s the basic code structure for a multiplication table, drawing from the sources:

# Let's pick a number for the table 🍎
num = 5

# We need to multiply 'num' by numbers 1 through 10.
# range(1, 11) will give us the numbers 1, 2, 3, ..., 10
for i in range(1, 11): # The variable 'i' will be 1, then 2, then 3, ... up to 10
    # Inside the loop, for each value of 'i':
    # Calculate the result: num multiplied by the current value of i
    result = num * i

    # Print the line of the table. We can use formatted printing for a nice output!
    print(f"{num} times {i} is {result}") # This line runs 10 times!

# After the loop finishes (i.e., range(1, 11) is exhausted), the program continues here.
print("Finished printing the table! 👍")

Let’s trace what happens in the loop:

1. The variable num is set to 5.
2. The for loop starts, using range(1, 11). This generates numbers starting from 1 and going up to (but not including) 11. So, i will take values 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.
3. First Iteration: i is 1.
   • result is calculated as num * i which is 5 * 1, so result is 5.
   • print(f"{num} times {i} is {result}") prints “5 times 1 is 5”.
4. Second Iteration: i is 2.
   • result is calculated as num * i which is 5 * 2, so result is 10.
   • print(f"{num} times {i} is {result}") prints “5 times 2 is 10”.
5. This continues for every number generated by range(1, 11).
6. Last Iteration: i is 10.
   • result is calculated as num * i which is 5 * 10, so result is 50.
   • print(f"{num} times {i} is {result}") prints “5 times 10 is 50”.
7. range(1, 11) has no more numbers. The loop finishes.
8. The code after the loop runs: print("Finished printing the table! 👍").

This way, the for loop automatically handles going through each number (1 to 10) and performing the multiplication and printing for us! 🎉 It replaces the need to write 10 separate print statements.

Using range(start, stop) is shown in the sources to specify the starting and ending points for the loop. If we had used range(10) as in some basic examples, i would go from 0 to 9, which might not be what we want for a standard multiplication table. range(1, 11) correctly gives us the numbers 1 through 10.

Just like calculating factorial or adding numbers, multiplication tables are a clear instance where the predictable number of steps makes the for loop with range() the perfect tool. You can easily adapt this code to print the table for any number by changing the value of the num variable. 👍