Python/C3/Loops/English-timed

Visual Cue	Narration
0:01	Hello Friends and Welcome to the tutorial on 'loops' in Python.
0:05	At the end of this tutorial, you will be able to, use the for loop use the while loop Use break, continue and pass statements to play around with loops.
0:17	Before beginning this tutorial,we would suggest you to complete the tutorial on "Getting started with for" and "Conditionals".
0:24	Let us start our ipython interpreter.
0:28	Type ipython in the terminal
0:32	We shall first begin with the while loop.
0:34	The while loop is used for repeated execution as long as a condition is True .
0:39	Let us print the squares of all the odd numbers less than 10, using the while loop.
0:45	Type i = 1 while i less than 10 colon print i multiply by i i += 2
1:19	This loop prints the squares of the odd numbers below 10.
1:23	The while loop, repeatedly checks if the condition is true and executes the block of code within the loop, if it is.
1:30	As with any other block in Python, the code within the while block is indented to the right by 4 spaces.
1:41	Pause the video here, try out the following exercise and resume the video.
1:48	Write a while loop to print the squares of all the even numbers below 10.
1:55	Switch to the terminal for solution.
1:58	Type i = 2 while i less than 10 colon print i multiply by i i += 2
2:27	Let us now solve the same problem of printing the squares of all odd numbers less than 10, using the for loop.
2:34	As we know, the for loop iterates over a list or any other sequential data type.
2:40	So, we use the range function to get a list of odd numbers below 10, and then iterate over it and print the required stuff.
2:48	Type for n in range within bracket 1 comma 10 comma 2 colon print n multiply by n
3:07	We can see that we got the same output as before.
3:10	Note that the lines of code are less.
3:13	Pause the video here, try out the following exercise and resume the video.
3:19	Write a for loop to print the squares of all the even numbers below 10.
3:24	Switch to the terminal
3:26	Type for n in range within bracket 2 comma 10 comma 2 colon print n multiply by n
3:46	Let us now look at how to use the keywords, pass , break and continue .
3:52	As we already know, pass is just a syntactic filler.
3:56	It is used for the sake of completion of blocks, that do not have any code within them.
4:02	Type for n in range within bracket 2 comma 10 comma 2 colon pass And Enter.
4:20	break is used to break out of the innermost loop.
4:24	The while loop to print the squares of all the odd numbers below 10, can be modified using the break statement, as follows
4:31	Type = 1 while True colon print i multiply by i i += 2 if i is less than 10 colon break
5:10	So we got a syntax error because 'if' is not inside the while loop So type while True colon print i multiply by i i += 2 if i less than 10 colon break Make sure that 'if' is inside the while loop.
5:42	continue is used to skip execution of the rest of the loop on this iteration and continue to the end of this iteration.
5:50	So, we wish to print the squares of all the odd numbers below 10, which are not multiples of 3, we would modify the for loop as follows.
6:03	So, in terminal, Type for n in range within bracket 1 comma 10 comma 2 colon if n modulo 3 == 0 colon continue print n multiply by n
6:36	Now Pause the video here, try out the following exercise and resume the video.
6:41	Using the continue keyword modify the for loop, with the range(2 comma 10 comma 2) , to print the squares of even numbers below 10, which are multiples of 4.
6:53	(Do not modify the range function call.)
6:59	Now Switch to the terminal for solution.
7:02	Type for n in range within bracket 2 comma 10 comma 2 colon if n modulo 4 colon continue print n multiply by n
7:30	This brings us to the end of this tutorial.
7:33	In this tutorial, we have learnt to, 1. Iterate over a sequence using ``for and ``while loops.
7:38	2. Break out of loops using ``break statement.
7:42	3. Skip iterations using ``continue statement.
7:45	4. Use the ``pass statement in a loop.
7:49	Here are some self assessment questions for you to solve
7:52	1. Given range(1 comma 4) ; Write a code to print only the number 1.
8:01	2.Second one is, Which statement do you use to skip iterations. - break - pass - continue
8:10	And the answers,
8:12	1. First one, We can use the break statement in a for loop as, colon colon
8:21	for i in range within bracket 1 comma 4 colon
8:27	Then print i break
8:30	And second one, In order to skip iterations,we make use of the continue statement.
8:37	Hope you have enjoyed this tutorial and found it useful.

Contributors and Content Editors

Gaurav, Kavita salve, Minal, PoojaMoolya, Sneha