Tutorial on Comparison Operators in MicroPython

Comparison operators in MicroPython are used to compare two values. They return a boolean value, either True or False, based on the comparison. These operators are commonly used in control flow structures like if statements and loops to make decisions.

This tutorial will guide you through the comparison operators in MicroPython with code examples to demonstrate their use.

Table of Contents:

1. Overview of Comparison Operators

MicroPython supports the following comparison operators:

2. Equality (==)

The equality operator == checks if two values are equal. If they are equal, it returns True; otherwise, it returns False.

Syntax:

result = a == b

Example:

a = 5
b = 5

result = a == b
print(result)  # Output: True

Explanation:

Since both a and b are equal, the comparison returns True.

3. Inequality (!=)

The inequality operator != checks if two values are not equal. If they are not equal, it returns True; otherwise, it returns False.

Syntax:

result = a != b

Example:

a = 5
b = 3

result = a != b
print(result)  # Output: True

Explanation:

Since a is not equal to b, the comparison returns True.

4. Greater Than (>)

The greater than operator > checks if the value on the left is greater than the value on the right. It returns True if the left value is greater.

Syntax:

result = a > b

Example:

a = 10
b = 5

result = a > b
print(result)  # Output: True

Explanation:

Since 10 is greater than 5, the comparison returns True.

5. Less Than (<)

The less than operator < checks if the value on the left is less than the value on the right. It returns True if the left value is less.

Syntax:

result = a < b

Example:

a = 3
b = 7

result = a < b
print(result)  # Output: True

Explanation:

Since 3 is less than 7, the comparison returns True.

6. Greater Than or Equal To (>=)

The greater than or equal to operator >= checks if the value on the left is either greater than or equal to the value on the right. It returns True if the left value is greater than or equal to the right.

Syntax:

result = a >= b

Example:

a = 8
b = 8

result = a >= b
print(result)  # Output: True

Explanation:

Since 8 is equal to 8, the comparison returns True.

7. Less Than or Equal To (<=)

The less than or equal to operator <= checks if the value on the left is either less than or equal to the value on the right. It returns True if the left value is less than or equal to the right.

Syntax:

result = a <= b

Example:

a = 5
b = 10

result = a <= b
print(result)  # Output: True

Explanation:

Since 5 is less than 10, the comparison returns True.

8. Using Comparison Operators with Strings

Comparison operators can also be used with strings. In MicroPython, strings are compared lexicographically, which means the comparison is based on the alphabetical order of the characters.

Example:

str1 = "apple"
str2 = "banana"

# Comparing strings
result = str1 < str2
print(result)  # Output: True

Explanation:

Since “apple” comes before “banana” in alphabetical order, the comparison returns True.

9. Chaining Comparison Operators

MicroPython allows chaining of comparison operators. This can be useful when you need to check if a value lies within a certain range.

Example:

x = 15

# Chaining comparison operators
result = 10 < x < 20
print(result)  # Output: True

Explanation:

The expression 10 < x < 20 checks if x is greater than 10 and less than 20. Since x = 15, the expression returns True.

10. Practical Examples

Example 1: Checking Age Eligibility

age = 18

# Check if age is within the voting age range
if age >= 18:
    print("You are eligible to vote.")
else:
    print("You are not eligible to vote.")

Output:

You are eligible to vote.

Example 2: Grading System

score = 85

# Use comparison operators to assign grades
if score >= 90:
    print("Grade: A")
elif score >= 80:
    print("Grade: B")
elif score >= 70:
    print("Grade: C")
else:
    print("Grade: F")

Output:

Grade: B

Example 3: Range Check

temperature = 22

# Check if temperature is within a comfortable range
if 18 <= temperature <= 25:
    print("The temperature is comfortable.")
else:
    print("The temperature is not comfortable.")
	

Output:

The temperature is comfortable.

Conclusion

Comparison operators are fundamental to decision-making in MicroPython. They allow you to compare values and execute code based on the result.

You now know how to:

Use equality and inequality operators (==, !=).
Compare values using greater than (>), less than (<), greater than or equal to (>=), and less than or equal to (<=).
Apply these operators to both numeric and string values.
Chain comparison operators for more complex conditions.

Understanding and using comparison operators effectively will enable you to write more dynamic and responsive code in your MicroPython projects.