Functions are a way to make your code more organized and easier to understand. They are like little machines that you can use over and over again in your code.

To create a function, you need to give it a name and then write what it does. You can also give it some inputs, like numbers or strings, that it will use to do its job.

For example, imagine you wanted to make a function that adds two numbers together. You could call it “add” and write the code like this:

def add(num1, num2):
    result = num1 + num2
    return result

Now, whenever you want to add two numbers together, you can just call the “add” function and give it the two numbers you want to add:

result = add(5, 7)

The “add” function will take those two numbers, add them together, and then return the result, which you can store in a variable called “result”.

Functions are really helpful because they can make your code shorter, easier to read, and easier to test.

Examples to try

Here are some more examples of functions in MicroPython on Raspberry Pi Pico:

Example 1: Adding Two Numbers

def add_numbers(a, b):
    result = a + b
    return result

# Test the function
print(add_numbers(2, 3)) # Output: 5
print(add_numbers(5, 10)) # Output: 15

Example 2: Counting Even Numbers

def count_even_numbers(numbers):
    count = 0
    for num in numbers:
        if num % 2 == 0:
            count += 1
    return count

# Test the function
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print(count_even_numbers(numbers)) # Output: 5

Example 3: Finding the Maximum Number in a List

def find_max(numbers):
    max_num = numbers[0]
    for num in numbers:
        if num > max_num:
            max_num = num
    return max_num

# Test the function
numbers = [3, 9, 2, 5, 1, 8, 4, 7, 6]
print(find_max(numbers)) # Output: 9

MicroPython on Raspberry Pi Pico provides several data structures for storing and manipulating data. These include lists, tuples, sets, and dictionaries. Loops are a powerful tool for iterating over these data structures and performing operations on their elements.

Let’s take a look at some examples of how loops can be used to iterate over data structures in MicroPython.

1. Iterating over a List

A list is a collection of items, and we can iterate over it using a for loop. Here’s an example:

# Create a list of numbers
numbers = [1, 2, 3, 4, 5]

# Iterate over the list and print each number
for number in numbers:
    print(number)

In this example, we create a list of numbers and then iterate over it using a for loop. For each number in the list, we print it to the console.

2. Iterating over a Tuple

A tuple is similar to a list, but it is immutable, which means it cannot be modified once it is created. Here’s an example of how to iterate over a tuple using a for loop:

# Create a tuple of fruits
fruits = ('apple', 'banana', 'cherry')

# Iterate over the tuple and print each fruit
for fruit in fruits:
    print(fruit)

In this example, we create a tuple of fruits and then iterate over it using a for loop. For each fruit in the tuple, we print it to the console.

3. Iterating over a Set

A set is an unordered collection of unique items. We can iterate over a set using a for loop just like we do with lists and tuples. Here’s an example:

# Create a set of colors
colors = {'red', 'green', 'blue'}

# Iterate over the set and print each color
for color in colors:
    print(color)

In this example, we create a set of colors and then iterate over it using a for loop. For each color in the set, we print it to the console.

4. Iterating over a Dictionary

A dictionary is a collection of key-value pairs. We can iterate over a dictionary using a for loop, but we need to use the items() method to access both the keys and values. Here’s an example:

# Create a dictionary of students and their grades
grades = {'Alice': 85, 'Bob': 90, 'Charlie': 95}

# Iterate over the dictionary and print each student and their grade
for student, grade in grades.items():
    print(f'{student}: {grade}')

In this example, we create a dictionary of students and their grades and then iterate over it using a for loop. For each student and their corresponding grade, we print them to the console.

Loop control statements are used to alter the normal flow of execution within loops. They can be used to skip iterations or terminate loops prematurely based on certain conditions. In MicroPython on Raspberry Pi Pico, there are three loop control statements: break, continue, and pass.

1. Break statement:
   The break statement is used to terminate a loop prematurely. When a break statement is encountered within a loop, the loop is immediately exited and program execution continues with the statement immediately following the loop. The break statement can be used with both for and while loops.

Here’s an example:

for i in range(1, 11):
    if i == 5:
        break
    print(i)

In this example, the loop will iterate over the values from 1 to 10. However, when i equals 5, the break statement is encountered and the loop is terminated prematurely. As a result, only the values from 1 to 4 will be printed.

2. Continue statement:
   The continue statement is used to skip the current iteration of a loop and move on to the next iteration. When a continue statement is encountered within a loop, the remaining statements within the loop for that iteration are skipped and the loop moves on to the next iteration. The continue statement can be used with both for and while loops.

Here’s an example:

for i in range(1, 11):
    if i % 2 == 0:
        continue
    print(i)

In this example, the loop will iterate over the values from 1 to 10. However, when i is even, the continue statement is encountered and the remaining statements for that iteration are skipped. As a result, only the odd values from 1 to 10 will be printed.

3. Pass statement:
   The pass statement is used to do nothing. It can be used as a placeholder when a statement is required syntactically, but no action is needed. The pass statement is typically used when a block of code is not yet implemented but is required for the program to run without error.

Here’s an example:

for i in range(1, 11):
    pass

In this example, the loop will iterate over the values from 1 to 10. However, the pass statement does nothing, so the loop will simply run through all iterations without doing anything. The pass statement can be used with both for and while loops.

Loop control statements are a useful tool in programming, as they allow us to alter the normal flow of execution within loops based on certain conditions. The break statement can be used to terminate a loop prematurely, the continue statement can be used to skip the current iteration and move on to the next iteration, and the pass statement can be used as a placeholder when no action is needed.

Sure, here is an example of how you can use continue, pass, and break statements in a loop:

# Example of using loop control statements in MicroPython

# Loop from 1 to 10
for i in range(1, 11):
    # If i is even, skip to the next iteration
    if i % 2 == 0:
        continue

    # If i is 5, do nothing and continue to the next iteration
    if i == 5:
        pass

    # If i is greater than 8, break out of the loop
    if i > 8:
        break

    # Print the value of i
    print(i)

In this example, the continue statement is used to skip over even numbers in the loop. The pass statement is used to do nothing and simply continue to the next iteration when the value of i is 5. Finally, the break statement is used to exit the loop when the value of i becomes greater than 8.

When you run this code, you will see the following output:

1
3
7

As you can see, the even numbers (2, 4, 6, 8, and 10) are skipped over with the continue statement. The value of 5 does nothing with the pass statement, and the loop stops when the value of i reaches 9 because of the break statement.

Nested loops in MicroPython on Raspberry Pi Pico refer to the use of one loop inside another loop. The inner loop is executed multiple times for each iteration of the outer loop. This technique is useful when we want to perform repetitive tasks or calculations on a set of data.

To create nested loops in MicroPython on Raspberry Pi Pico, we simply need to place one loop inside another loop. Here’s an example:

for i in range(3):
    for j in range(2):
        print(i, j)

In this example, we have an outer loop that iterates from 0 to 2, and an inner loop that iterates from 0 to 1. For each iteration of the outer loop, the inner loop is executed twice. The output of this code would be:

0 0
0 1
1 0
1 1
2 0
2 1

We can also use nested loops to access and modify elements of a two-dimensional list or array. Here’s an example:

matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

for row in matrix:
    for element in row:
        print(element)

In this example, we have a two-dimensional list called matrix. The outer loop iterates over each row of the matrix, while the inner loop iterates over each element in the current row. The output of this code would be:

1
2
3
4
5
6
7
8
9

Nested loops can also be used to perform more complex calculations or operations.