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Range Function

The range() function in Python is a built-in function that generates a sequence of numbers.

It is often used for iterating over a sequence with loops, particularly when you need to execute a loop a specific number of times.

This is ideal for handling tasks that involve a predictable repetition pattern, such as restocking shelves or scheduling sales in a grocery store setting.

Let's see how Alex utilizes the range() function to manage routine tasks in our grocery store scenario efficiently:

Syntax and Arguments

The range() function can take up to three arguments, making it versatile for various looping scenarios.

Here is the general syntax for the range function:


python

start: this is the first number of the sequence. It's optional, and if you don't include it, the sequence will start at 0.
stop: this is the last number of the sequence, but the sequence will stop just before this number. This argument is required.
step: this is the amount you add (or subtract) between each number in the sequence. It's optional, and if you don't include it, the sequence will increase by 1 each time.

Now that you have a grasp of the range() function syntax, let’s explore some examples to see how each argument — start, stop, and step — influences the behavior of loops.

A Single Argument

When the range() function is given a single argument, it treats this as the stop parameter.

In our example, it generates a sequence of 7 elements starting from 0 and ending at 6. The loop iterates over these elements, representing the first 7 days the store is open.


              123
            
# Announce store opening every day for 7 days
for day in range(7):
    print(f"Good morning! The store is now open on day {day}.")

Note

The sequence starts at 0 and ends at 6. This happens because Python often starts counting from 0, which reduces the need to adjust indexing in many situations.

Two Arguments

When two arguments are provided, like 25 (start) and 32 (stop), range() generates a sequence from 25 to 31 (since the stop value is excluded from the sequence).


              123
            
# Planning seasonal sale days in the last week of December
for day in range(25, 32):
    print(f"Seasonal sale on December {day}.")

Note

With this method of indexing, where the end element is excluded, you can easily calculate the number of elements in the sequence by subtracting the start argument from the stop argument. For example, 32 - 25 = 7, meaning there are 7 elements in the sequence.

Three Arguments

By adding a third argument to range(), you introduce a step value, which defines the increment between each number in the sequence.

In this example, range() takes 1 (start), 13 (stop), and 3 (step), producing the numbers 1, 4, 7, 10. These can represent the starting hours of staff shifts during a 12-hour workday.


              123
            
# Schedule staff shifts every three hours throughout a 12-hour day
for hour in range(1, 13, 3):
    print(f"Staff shift starts at hour {hour}.")

Example Application

With the range() function, we can schedule tasks for each day of the week to make sure all sections of the store are covered.

This loop runs 7 times because range(7) creates numbers from 0 to 6 (a total of 7 elements). In each loop, the variable day takes a value from 0 to 6, which is then used to access elements from both weekly_tasks and weekdays lists.


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# List of daily tasks for a week
weekly_tasks = [
    "Restock Fruits",
    "Clean Dairy Section",
    "Review Meat Inventory",
    "Restock Vegetables",
    "Check Bakery Expiry Dates",
    "Organize Front Displays",
    "Prepare Weekly Sales Report"
]

# List of weekdays corresponding to each task
weekdays = [
    "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"
]

# Loop through each day using the range function
for day in range(7):
    task = weekly_tasks[day]  # Access the task corresponding to the current day
    weekday = weekdays[day]   # Access the corresponding weekday
    print(f"{weekday} Task: {task}")

Task

Swipe to start coding

Use two lists — weekdays and daily_promotions — to print the promotion assigned to each day of the week.

Use a for loop with the range() function to iterate through the list indices.
In each iteration:
- Get the current weekday from the weekdays list.
- Get the corresponding promotion from daily_promotions using the same index.
Print both values in the specified format.

Output Requirements

For each day, print:
<weekday>: Promotion on <promotion>

Note

Ensure both lists have the same number of items to avoid indexing errors.

Solution

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Section 5. Chapter 3

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Range Function

The range() function in Python is a built-in function that generates a sequence of numbers.

It is often used for iterating over a sequence with loops, particularly when you need to execute a loop a specific number of times.

This is ideal for handling tasks that involve a predictable repetition pattern, such as restocking shelves or scheduling sales in a grocery store setting.

Let's see how Alex utilizes the range() function to manage routine tasks in our grocery store scenario efficiently:

Syntax and Arguments

The range() function can take up to three arguments, making it versatile for various looping scenarios.

Here is the general syntax for the range function:


python

start: this is the first number of the sequence. It's optional, and if you don't include it, the sequence will start at 0.
stop: this is the last number of the sequence, but the sequence will stop just before this number. This argument is required.
step: this is the amount you add (or subtract) between each number in the sequence. It's optional, and if you don't include it, the sequence will increase by 1 each time.

Now that you have a grasp of the range() function syntax, let’s explore some examples to see how each argument — start, stop, and step — influences the behavior of loops.

A Single Argument

When the range() function is given a single argument, it treats this as the stop parameter.

In our example, it generates a sequence of 7 elements starting from 0 and ending at 6. The loop iterates over these elements, representing the first 7 days the store is open.


              123
            
# Announce store opening every day for 7 days
for day in range(7):
    print(f"Good morning! The store is now open on day {day}.")

Note

The sequence starts at 0 and ends at 6. This happens because Python often starts counting from 0, which reduces the need to adjust indexing in many situations.

Two Arguments

When two arguments are provided, like 25 (start) and 32 (stop), range() generates a sequence from 25 to 31 (since the stop value is excluded from the sequence).


              123
            
# Planning seasonal sale days in the last week of December
for day in range(25, 32):
    print(f"Seasonal sale on December {day}.")

Note

With this method of indexing, where the end element is excluded, you can easily calculate the number of elements in the sequence by subtracting the start argument from the stop argument. For example, 32 - 25 = 7, meaning there are 7 elements in the sequence.

Three Arguments

By adding a third argument to range(), you introduce a step value, which defines the increment between each number in the sequence.


              123
            
# Schedule staff shifts every three hours throughout a 12-hour day
for hour in range(1, 13, 3):
    print(f"Staff shift starts at hour {hour}.")

Example Application

With the range() function, we can schedule tasks for each day of the week to make sure all sections of the store are covered.


              123456789101112131415161718192021
            
# List of daily tasks for a week
weekly_tasks = [
    "Restock Fruits",
    "Clean Dairy Section",
    "Review Meat Inventory",
    "Restock Vegetables",
    "Check Bakery Expiry Dates",
    "Organize Front Displays",
    "Prepare Weekly Sales Report"
]

# List of weekdays corresponding to each task
weekdays = [
    "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"
]

# Loop through each day using the range function
for day in range(7):
    task = weekly_tasks[day]  # Access the task corresponding to the current day
    weekday = weekdays[day]   # Access the corresponding weekday
    print(f"{weekday} Task: {task}")

Task

Swipe to start coding

Use two lists — weekdays and daily_promotions — to print the promotion assigned to each day of the week.

Use a for loop with the range() function to iterate through the list indices.
In each iteration:
- Get the current weekday from the weekdays list.
- Get the corresponding promotion from daily_promotions using the same index.
Print both values in the specified format.

Output Requirements

For each day, print:
<weekday>: Promotion on <promotion>

Note

Ensure both lists have the same number of items to avoid indexing errors.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 5. Chapter 3

Switch to desktop for real-world practiceContinue from where you are using one of the options below