If Statements

If Statements

Conditionals: Features of programming language that allows different computations to occur based on decision making.

• Conditionals are dependent on Boolean expressions that are evaluated to True or False.

• Different texts will define conditionals to be statements, expressions, or constructs.

• The use of conditionals is the way to control the flow of a program.

if statement

• if is a built-in keyword in Python that allows us to write conditional statements.

• if statements will only execute their own block of code if its boolean condition evaluates to True.

• if the boolean condition doesn’t evaluate to True, the program will skip its block of code

• Block of code or Code Block in python are started by a (:) colon and indentation. (Examine the example below)

# if statement formatting template

if (boolean_expression_here): # notice the colon to start the if's code block
    # single indentation

    code written here
# end of the if statement

code written here ... outside of the if statement

# Code Example 1
num1 = 10
num2 = 42
target = 34

if target >= num1 and target <= num2:
    print(target, 'is in between', num1, 'and', num2)

Output:
34 is in between 10 and 42

# Code Example 2
word = 'Hello'

if len(word) >= 6:
    print(word, 'is too long.')

print(word)

# Notice that the message 'Hello is too long' is not outputted.
# This is because len(word) is less than 6 hence len(word) >= 6 is False

Output:
Hello