How To Print Numbers In Reverse Order In Python

In this tutorial, we will learn how to print numbers in reverse order using Python. We will explore different ways to achieve this using various Python constructs, such as loops and slicing techniques. By the end of this tutorial, you will be able to reverse the order of any sequence of numbers using Python.

Step 1: Using a For Loop and Range Function

We can use a for loop to iterate through the numbers and the range() function to specify the start, stop, and step values, with a negative step value to reverse the sequence. Here’s an example:

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start_number = 10
end_number = 0
step_value = -1
 
for i in range(start_number, end_number, step_value):
    print(i)

In this example, start_number is set to 10, end_number is set to 0, and step_value is set to -1. The range function will create a sequence of numbers starting from the start_number and stop before the end_number, decrementing by the absolute value of step_value.

The output of the code would be:

10
9
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3
2
1

Step 2: Using List Slicing

Another way to reverse the order of numbers is by using **list slicing**. If the numbers are already stored in a list, we can simply slice the list in reverse order.

Here’s an example:

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numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
reversed_numbers = numbers[::-1]
 
for num in reversed_numbers:
    print(num)

In this example, we use the slice notation [::-1] to create a new list that is a reversed copy of the original list. We then use a for loop to print each number in the reversed list.

The output of the code would be:

10
9
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3
2
1

Step 3: Using the Built-in Reversed Function

Python provides a built-in reversed() function that can be used to reverse the order of any iterable, such as lists, tuples, or strings.

Here’s an example:

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numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
reversed_numbers = reversed(numbers)
 
for num in reversed_numbers:
    print(num)

In this example, we use the reversed() function to reverse the order of the numbers list, returning a reversed iterator object. We then use a for loop to print each number in the reversed iterator object.

The output of the code would be:

10
9
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3
2
1

Full Code

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start_number = 10
end_number = 0
step_value = -1
 
for i in range(start_number, end_number, step_value):
    print(i)
 
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
reversed_numbers = numbers[::-1]
 
for num in reversed_numbers:
    print(num)
 
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 
reversed_numbers = reversed(numbers)
 
for num in reversed_numbers:
    print(num)

Conclusion

Now you know how to print numbers in reverse order using Python. We’ve seen three different methods to achieve this using a for loop with the range function, list slicing, and the built-in reversed() function. In most cases, you can use any of these approaches depending on your preference and the specific requirements of your code.