Q4 LESSON 2: Looping Structures - WHILE and FOR Loops

Q4 LESSON 2-MODULE 2: HANDS ACTIVITY 4.2

Python Activities 8 & 9 - Looping Structures – WHILE Loops  and Looping Structures – FOR Loops

Poll

What’s your favorite fast food restaurant?

There are TWO rules that must hold in playing the game.

• “Ready to be riddled?” is a LOGICALBRAIN TEASER PUZZLE GAME. The game will enhance your critical thinking ability.

• ALL OF YOU will be the participants and must answer by analyzing the RIDDLE to be shown.

• You will be given a duration of 30 seconds to answer.

• Let's Get it on Pythons!

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Five letter word

What five-letter word gets shorter when you add two letters to it?

ANSWER: Shorter

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More is less

The more there is, the less you see. What is it?

ANSWER: Fog

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In the light

I exist only when there is light, but direct light kills me. What am I?

ANSWER: A Shadow

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Face and hands

What has a face and two hands but no arms or legs?

ANSWER: A Clock

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While it dries

What gets wetter while it dries?

ANSWER: A Towel

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Around the world

What travels around the world but stays in the same corner?

ANSWER: A Stamp

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In the planets

You can find it in Mercury, Earth, Mars, Jupiter, and Saturn, but not in Venus or Neptune. What is it?

ANSWER: The letter "R"

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Breaks without fall

What breaks but never falls, and what falls but never breaks?

ANSWER: Morning and Night

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Meeting directions

A woman is a bit confused about where her meeting is. Starting on the fourth floor, she climbs up five stories, down seven stories, up six stories, down three stories, and up four stories again. What floor is she on?

ANSWER: The ninth floor

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The city bus

You’re driving a city bus. At the first stop, five women get on. At the second stop, one woman gets off and two men get on. At the third stop, three children get on. The bus is white and it’s raining outside in March. What color is the bus driver’s hair?

ANSWER: Whatever color your hair is. You’re the bus driver.

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Moving while seated

Who makes moves while sitting down?

ANSWER: A chess player. 

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Down and up

I come down, but I never go up. What am I?

ANSWER: Rain

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Make, save, change, raise

People make me, save me, change me, raise me. What am I?

ANSWER: Money

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Always in front

What is always in front of you but can’t be seen?

ANSWER: The future

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Once a minute

What can be seen once in a minute, twice in a moment, and never in a thousand years?

ANSWER: The letter “M.”

Continuation of Presentation of Learner's Tasks Management System

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How important "Modularizing Code" in programming?

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How do you write if-else, nested if/else and elif statements in Python and state their importance in programming?

LOOPING

A looping structure allows a block of code to be repeated one or more times. 

Why LOOP at all?

• The main reason why we need looping in programs is to make complex problems simpler as sometimes we won’t be writing the whole program to go through each query if the functionality is same.

• The main advantages of using loops in python is that it saves your time, you don’t have to write the same code every time to perform the same functionality; also loops make your code look clean.

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What is Loop in Python?

What is the syntax of for loop in Python?

WHILE Loop

A while loop in python continues to execute the code as long as the given condition is true, if it becomes false, then the loop stops.

Another reason to use while loop is when we aren’t sure about how many times to iterate.

WHILE Loop sample program structure

Types of WHILE Loop

• An Infinite Loop

• Be careful while using a while loop. Because if you forget to increment the counter variable in python, or write flawed logic, the condition may never become false.

• In such a case, the loop will run infinitely, and the conditions after the loop will starve. To stop execution, press Ctrl+C.

Types of WHILE Loop

• The else statement for while loop

• A while loop may have an else statement after it. When the condition becomes false, the block under the else statement is executed.

• However, it doesn’t execute if you break out of the loop or if an exception is raised.

Types of WHILE Loop

• Single Statement while

• Like an if statement, if we have only one statement in while’s body, we can write it all in one line.

• You can see that there were two statements in while’s body, but we used semicolons to separate them. Without the second statement, it would form an infinite loop

FOR Loop

For loop is a python loop which repeats a group of statements for a given number of times.

It is always a good practice to use the for loop when we know the number of iterations.

Types of FOR Loop

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How do you write a loop in Python?

How many types of loops are there in Python?

LOOP Control Statement

• Sometimes, you may want to break out of normal execution in a loop.

  
  

• For this, we have three keywords in Python- break, continue, and pass.

Break Statement

When you put a break statement in the body of a loop, the loop stops executing, and control shifts to the first statement outside it.

You can put it in a for or while loop.

Continue Statement

When the program control reaches the continue statement, it skips the statements after ‘continue’.

It then shifts to the next item in the sequence and executes the block of code for it.

You can use it with both for and while loops.

Pass Statement

In Python, we use the pass statement to implement stubs.

When we need a particular loop, class, or function in our program, but don’t know what goes in it, we place the pass statement in it.

It is a null statement. The interpreter does not ignore it, but it performs a no-operation (NOP).