Category: Development Kit

For loops are one of the most commonly used loops in programming, including MicroPython on Raspberry Pi Pico. They allow you to repeat a set of instructions a specific number of times, making your code more efficient and concise.

In MicroPython, a for loop is used to iterate over a sequence of values, such as a list, tuple, or string. The general syntax for a for loop in MicroPython is as follows:

for variable in sequence:
    # Code to execute for each item in the sequence

Here, variable is a temporary variable that takes on the value of each item in the sequence. The code block under the for statement is executed for each item in the sequence, with variable taking on the value of each item in turn.

For example, let’s say we have a list of numbers and we want to print each number in the list:

numbers = [1, 2, 3, 4, 5]

for num in numbers:
    print(num)

In this code, num takes on the value of each item in the numbers list, and the print statement outputs each number in turn.

In addition to lists, for loops can also be used with other sequences such as tuples and strings. For example:

name = "John"

for char in name:
    print(char)

This code outputs each character in the string name, one character per line.

You can also use the built-in range() function with for loops in MicroPython. The range() function returns a sequence of numbers starting from 0 (by default) and incrementing by 1, up to a specified number. For example:

for i in range(5):
    print(i)

This code outputs the numbers 0 through 4, one number per line.

You can also specify a starting value and a step size for the range() function. For example:

for i in range(1, 10, 2):
    print(i)

This code outputs the odd numbers from 1 to 9, one number per line.

While loops in MicroPython on Raspberry Pi Pico are used to execute a block of code repeatedly as long as a certain condition is true. The general syntax for a while loop is:

while condition:
    # code to execute

The condition is checked at the beginning of each iteration. If the condition is true, the code inside the loop is executed. Once the code has been executed, the condition is checked again, and the loop continues until the condition is false.

Here’s an example of a simple while loop:

i = 0
while i < 5:
    print(i)
    i += 1

In this example, the loop will continue to execute as long as i is less than 5. Inside the loop, the current value of i is printed, and i is incremented by 1. The loop will continue until i reaches 5, at which point the condition i < 5 will be false, and the loop will terminate.

It’s important to make sure that the condition in a while loop will eventually become false, otherwise the loop will continue to execute indefinitely, which is known as an infinite loop. An infinite loop can cause your program to hang or crash, so it’s important to make sure that your loop will eventually terminate.

Here’s an example of an infinite loop:

i = 0
while i < 5:
    print(i)

In this example, the condition i < 5 will always be true, since i is never incremented. This will cause the loop to continue to execute indefinitely, which is not what we want.

While loops can be useful for a variety of tasks, such as reading data from sensors, controlling motors, or performing other repetitive tasks. By using while loops, you can make your code more efficient and easier to read.

Loops are an essential part of any programming language, including MicroPython on Raspberry Pi Pico. They allow you to execute a block of code repeatedly, saving you time and effort. In this article, we’ve introduced you to the two types of loops in MicroPython: for loops and while loops.

What are Loops?
A loop is a programming construct that allows you to execute a block of code repeatedly until a specific condition is met. There are two types of loops in MicroPython: for loops and while loops.

For Loops
A for loop is used when you want to execute a block of code a fixed number of times. The syntax of a for loop in MicroPython is as follows:

for variable in sequence:
    # Code to execute

The variable is assigned to each element of the sequence in turn, and the code inside the loop is executed. Here’s an example:

for i in range(5):
    print(i)

This code will print the numbers from 0 to 4.

While Loops
A while loop is used when you want to execute a block of code repeatedly until a specific condition is met. The syntax of a while loop in MicroPython is as follows:

while condition:
    # Code to execute

The code inside the loop will be executed repeatedly until the condition becomes false. Here’s an example:

i = 0
while i < 5:
    print(i)
    i += 1

The code first initializes the value of i to 0. Then it enters the while loop and checks if the value of i is less than 5. Since i is initially 0, the condition is true and the loop begins.

The loop prints the current value of i using the print() function and then increments the value of i by 1 using the += operator. This process repeats until the value of i is no longer less than 5, at which point the loop ends and the program continues with the rest of the code.

When you run this code in a MicroPython environment such as Thonny IDE, the output will be:

0 1 2 3 4

This is because the loop executes five times, with the value of i being printed on each iteration.

Conditional statements in MicroPython on Raspberry Pi Pico are used to make decisions based on certain conditions. They allow us to execute a block of code only if a certain condition is true, or to execute a different block of code if the condition is false.

In MicroPython, we use the if, elif, and else keywords to create conditional statements. The general syntax for an if statement is:

if condition:
    # Code to execute if condition is True

If the condition is true, then the code inside the block is executed. If the condition is false, then the code inside the block is skipped.

Here’s an example of an if statement:

temperature = 25

if temperature > 30:
    print("It's hot outside!")

In this example, the condition temperature > 30 is false, so the code inside the block is not executed.

We can also use the else keyword to specify what code should be executed if the condition is false:

temperature = 25

if temperature > 30:
    print("It's hot outside!")
else:
    print("It's not that hot outside.")

In this case, since the condition is false, the code inside the else block is executed, and the output would be “It’s not that hot outside.”

We can also use the elif keyword to check multiple conditions:

temperature = 25

if temperature > 30:
    print("It's hot outside!")
elif temperature > 20:
    print("It's warm outside.")
else:
    print("It's not that hot outside.")

In this example, the first condition is false, so the elif condition is checked. Since temperature > 20 is true, the code inside the elif block is executed, and the output would be “It’s warm outside.”

Conditional statements can also be nested inside each other, to create more complex logic. For example:

x = 5
y = 10

if x > 0:
    if y > 0:
        print("Both x and y are positive.")
    else:
        print("x is positive but y is not.")
else:
    if y > 0:
        print("y is positive but x is not.")
    else:
        print("Both x and y are negative.")

In this example, the output would be “Both x and y are positive.” since both x and y are greater than 0.

elif statements can be nested in Python and MicroPython on Raspberry Pi Pico. You can use them to create more complex conditions that depend on multiple variables or factors.

Here’s an example of nested elif statements in MicroPython on Raspberry Pi Pico:

x = 5
y = 10

if x > y:
    print("x is greater than y")
elif x < y:
    print("x is less than y")
    if x < 0:
        print("x is negative")
    elif x == 0:
        print("x is zero")
    else:
        print("x is positive")
else:
    print("x is equal to y")

In this example, if x is less than y, the program checks whether x is negative, zero, or positive using nested elif statements. If x is greater than y, the program prints a message saying so. And if x is equal to y, the program prints a message saying that as well.

Note that when you nest elif statements, you must make sure that the indentation is correct to avoid syntax errors.