Control Structures in Python

Python if Condition Statements

• In Python, an if statement is like a decision-maker in your code.
• It helps your program make choices based on certain conditions.
• Imagine you're deciding whether to go outside: if it's sunny, you go out; if it's rainy, you stay inside.
• That's what if statements do in programming.

Here's how

1. Condition Check: You start with a condition, which is like a question your program asks. Is it sunny?
2. Decision: Then, based on the answer (True or False), your program decides what to do next. If it's sunny (True), go out; otherwise (False), stay inside.

• condition is the question your program asks.
• If the condition is True, the code inside the if block (indicated by the indentation) is executed.
• If the condition is False, the code inside the if block is skipped. • If the condition is False, the transfer of the code is prevented.

1temperature = 25  # Suppose the temperature is 25 degrees Celsius.
2
3if temperature > 30:
4    print("It's a hot day!")  # This line will only run if the temperature is greater than 30.
5print("It's a hot day!") # This line only runs if the temperature is above 30 degrees.
6print("Enjoy your day!")  # This line will always run.
7

In this code:

• We set the temperature variable to 25.
• The if statement checks if the temperature is greater than 30. If it is, it prints "It's a hot day!" because the condition is true.
• • Report if fever is above 30 degrees. If so, "It's a hot day!" in summer.
• The print("Enjoy your day!") statement will always run, regardless of the temperature, because it's not part of the if block.

If-Else Condition in Python:

• Imagine you have to decide whether to take an umbrella when you go outside.
• You look at the sky, and if it's cloudy, you take the umbrella; if it's not, you leave it behind.
• This decision-making process is a lot like what the "if-else" condition does in Python.

What is it?

• The "if-else" condition is like a traffic signal for your program. It helps your program make choices based on certain conditions.
• If a specific condition is true, your program does one thing (like taking an umbrella), and if it's false, it does something else (like not taking an umbrella).

How does it work?

• You start with an "if" statement, which checks if a condition is true.
• If the condition is true, the code inside the "if" block runs.• If the condition is true, run the code in the "if" block.
• If the condition is false, the code inside the "else" block runs.

1weather = "rainy"
2
3if weather == "rainy":
4    take_umbrella()
5else:
6    enjoy_sunny_day()
7
8

• In this example, the program checks if the weather is "rainy." If it is, it takes an umbrella; otherwise, it enjoys a sunny day.
• It's like giving instructions to your program based on what's happening, just like you decide whether to take an umbrella based on the weather.

The "if-elif-else" Condition in Python

• The "if-elif-else" condition in Python is like making choices in your program.
• It allows you to decide what to do based on multiple conditions.
• Think of it as a series of questions you ask, one after the other, to determine the right action.

• You start with an "if" statement to check a condition. If it's true, the code inside the "if" block runs.

elif (Else If Statement):

• If the "if" condition is false, you can use "elif" to check another condition. It's like asking a different question.
• You can have multiple "elif" blocks to check various conditions.

• If none of the previous conditions are true, the "else" block runs. It's like having a default action.

• With "if-elif-else," you can create decision trees in your program, making it flexible and responsive to different scenarios.
• It's like having a conversation with your program, where it chooses what to say based on the answers you provide.

1# Get the current time in 24-hour format (e.g., 13:45 for 1:45 PM)
2current_time = int(input("Enter the current time (in 24-hour format): "))
3current_time = int(input("Please enter the current time (24-hour format):"))
4
5# Check the time and greet accordingly
6if current_time < 12:
7    print("Good morning!")
8elif current_time < 18:
9    print("Good afternoon!")
10else:
11    print("Good evening!")
12
13

1. It asks the user to input the current time in 24-hour format.
2. It uses the "if-elif-else" condition to check the time and print a greeting message based on the time of day.

• For example, if you input 9 as the current time, it will print "Good morning!"
• If you input 15, it will print "Good afternoon!" And if you input 20, it will print "If you enter 20, "Good night!" writer.
• Good evening!" This code demonstrates how you can use conditions to make decisions.