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Practice

Using Comparison Operators in Conditional Statements

One of the most important operators when writing conditional statements is the comparison operator.

Using comparison operators within conditional statements makes it easy to determine whether a condition is true or false.


Reviewing Comparison Operators​

First, let's review some common comparison operators used in Python:

  • == : Checks if two values are equal. a == b is true if a and b are equal.

  • != : Checks if two values are not equal. a != b is true if a and b are not equal.

  • > : Checks if the left value is greater than the right value. a > b is true if a is greater than b.

  • < : Checks if the left value is less than the right value. a < b is true if a is less than b.

  • >= : Checks if the left value is greater than or equal to the right value. a >= b is true if a is greater than or equal to b.

  • <= : Checks if the left value is less than or equal to the right value. a <= b is true if a is less than or equal to b.


Using Comparison Operators in Conditional Statements​

Let's examine how we can use comparison operators with conditional statements.


Comparing Numerical Values​

Let's write a program to check if a person is an adult by determining if they are 18 or older.

Comparing Numbers
age = 20

if age >= 18:
    print("You are an adult")
else:
    print("You are not an adult")

Here, the condition age >= 18 is true if age is greater than or equal to 18.

Since the value of age is 20, which is greater than 18, the message "You are an adult" will be printed.


Checking if Two Numbers are Equal​

You can use the == comparison operator to check if two numbers are equal.

The following is an example of comparing whether two numbers are equal.

Checking if Values are Equal
a = 10
b = 10

if a == b:
    print("The two numbers are equal")
else:
    print("The two numbers are not equal")

In the code above, since the values of a and b are both 10, the message "The two numbers are equal" will be printed.


Comparing Strings​

The == comparison operator can be used not only with numbers but also with strings.

To compare whether strings are equal, you can write the following:

Comparing Strings
password = input("Enter your password: ")

if password == "python123":
    print("Password matches")
else:
    print("Password does not match")

In this code, if the value of the user-input password matches "python123", the message "Password matches" will be printed.

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