Mastering Loops in Python: Automate Your Code with Efficiency and Ease

As an IT specialist, you can encounter situations where you must reuse a piece of code multiple times. For instance, when automating the collection of new registrations or applications on a website. Instead of repeatedly writing the same line of code, which is time-consuming and inefficient, you can create a function or use so-called loops.

Case study — loop for product codes

We will consider here one example that showcases the loops usage of the self-purchase systems found in stores. These systems allow customers to make purchases by entering product codes. To ensure a smooth and efficient experience, these systems typically employ a loop that checks for code entry every 20 seconds. This loop verifies whether the code has been typed, allowing customers to complete their transactions seamlessly.

You can use a few key loop options using Python’s range() function. The statement block within the loop is executed based on a condition checked at the beginning or end of each iteration.

There are two key options for conditional loops in Python:

1. For loop
2. While loop

Both options allow you to execute a piece of code repeatedly. The main difference between these two functions is quite clear. If we know the exact number of iterations in advance, we will use the “for” loop; otherwise — the “while” loop.

1. For loop

This function for allows you to repeatedly execute a block of code for each item in the sequence, like in our case. Four possible data types can be used infor loop, in particular, a list, tuple, string, or range.

We will elaborate on this point in more detail. Here are some examples of how the for loop can be used:

1. Iterate over a list:

python

fruits = ['apple', 'banana', 'orange']
for fruit in fruits:
    print(fruit)

Output:

apple
banana
orange

2. Iterate over a string:

python

message = "Hello, World!"
for char in message:
    print(char)

Output:

H
e
l
l
o
,
 
W
o
r
l
d
!

3. Iterate over a range of numbers:

python

for i in range(1, 6):
    print(i)

Output:

1
2
3
4
5

Solution For loop

We will use the ‘a list ‘ option since we want to iterate a list of product codes. So, let’s define the codes according to UPC (The Universal Product Code), which consists of 12 digits uniquely assigned to each trade item. It’s a sample data structure used for demonstration purposes.

Step 1: Define the product codes

python
product_codes = ["018375768312", "035674982241", "048293746356"]

After defining the list of products, we need to use for in function to iterate the code entry verification. In this case, we will use the function print to show the message about the verification.

Step 2: Perform the code checking loop

2.1. Specify a message

python

for code in product_codes:
    print("Checking code:")

2.2. Specify the number of iterations

Since our task is to check the code every 20 seconds, we must use the module import time. Python offers a wide range of modules you can import for various purposes. For example, math, random, os, json, etc. The time module in Python provides multiple functions to work with time-related operations. We import the time module to use the sleep() function, which allows us to introduce a delay in the code execution.
import time

import time

for _ in range(3):  # Replace 3 with the desired number of iterations
    code = input("Enter the product code: ")

3. Specify the interval between code checks

python

import time
# Simulating the 20-second interval
    time.sleep(20)

Thus, the unified code will look like this

import time

product_codes = ["018375768312", "035674982241", "048293746356"]

for code in product_codes:
    print("Checking code:", code)
    time.sleep(20)

Output:

Checking code: 018375768312
Checking code: 035674982241
Checking code: 048293746356

2. While loop

Another option is the while loop. This while loop accomplishes the same behavior as the for loop in the previous example. It iterates over each code in the product_codes list, prints the message, and waits for 20 seconds before moving on to the next code.

import time

product_codes = ["018375768312", "035674982241", "048293746356"]
index = 0
while index < len(product_codes):
    code = product_codes[index]
    print("Checking code:", code)
    index += 1
    time.sleep(20)

So, we have already viewed why and how to use import time and define product_codes. The novelty of this statement will be the usage of variables while index. We initialize the index variable to 0, which represents the current position in the product_codes list.

The while loop continues to execute as long as the index is less than the length of the product_codes list. Inside the loop, we retrieve the code at the current index from the product_codes list using product_codes[index].

We then print the message “Checking code:” followed by the code. After printing, we increment the index by 1 to move to the next code in the list. Finally, we use time.sleep(20) to introduce a 20-second delay before the next iteration of the loop.

It’s important to be cautious when using while loops to avoid creating infinite loops that don’t terminate. Ensure to include a condition that will eventually be met to exit the loop.

In conclusion, both for and while loops are powerful tools in programming that allow you to automate repetitive tasks. Understanding their syntax and usage allows you to optimize your code and improve efficiency.