Python and keyword

Python and keyword is a logical operator used for combining two or more expressions into a single expression, otherwise known as compound expression.

It is often used to create compound conditions, allowing programmers to make decisions based on multiple factors.

The outcome of a compound expression, where the individual expressions are joined by the and operator is True if all the individual expressions evaluate to True, and False if at least one of the expressions evaluates to False.

In other words, all the individual expressions that make up the compound expression must evaluate True to get an overall output of True. If any of the individual expressions evaluate as False, then the expression becomes False.

This operator is widely used in control structures such as the if statements and while statements for performing conditional tests. If the conditional test evaluates to True, then the preceding block of code is executed, otherwise, it will not be executed.

Example 1: Combining two boolean values

A boolean value is either True or False. The and operator can combine boolean values into a single expression known as a boolean expression.

Consider the example below, where the and operator is used to combine two boolean values, and the respective outputs of the compound expression formed.

result = True and True
print(result)

result = True and False
print(result)

result = False and True
print(result)

result = False and False
print(result)

output

True
False
False
False

Example 2: Combining more than two boolean values

You can also use the and operator to combine two or more boolean values into a single expression as shown below:

result = True and True and True
print(result)

result = True and True and False
print(result)

result = True and False and False
print(result)

result = False and False and False
print(result)

output

True
False
False
False

Example 3: Performing conditional tests

The and operator is also used in control structures for conditional tests. For instance, in the if statement, the and operator is used to combine two or more expressions together.

These individual expressions must evaluate to True before the block of code under the if statement will be executed.

Let’s look at how the and operator can be used in conditional tests in control statements.

num1 = int(input())
num2 = int(input())
num3 = int(input())
if (num1 < num1):
    print('yes')
else:
    print('no')

In the above example, there are two expressions, (num1 > num2) and (num2<num1). The only condition in which the underlying code after the if statement will be executed if the two statements evaluate to True.

If any of them evaluate to False, then the overall outcome will be False.

Example 4: and operator in while loop

Apart from the if statements, the and operator is also used for conditional tests in the while statements. In the example below, looping will only occur if the number entered is not equal to 0 and must be greater than 1.

num =  int(input('enter a number: '))
count = 0
sum = 0

while num != 0 and num > 1:
    sum += num
    count+=1
    num =  int(input('enter a number: '))

average = sum/count

print(sum)
print(average)

Example 5: Combining arithmetic expressions

The example below is arithmetic expressions combined together with the and operator.

num = 10 
result = num > 5 and num %2==0 
print(result)

output

True

Conclusion

The and keyword in Python serves as a valuable tool for combining conditions and performing logical operations.

Whether you need to evaluate multiple conditions, chain expressions, or benefit from short-circuit evaluation, the ‘and’ keyword provides a flexible and efficient solution.