Difference between revisions of "Python/C3/Loops/English-timed"

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{| border=1
 
{| border=1
−
!Visual Cue
+
|'''Time'''
−
!Narration
+
|'''Narration'''
 +
 
 
|-
 
|-
−
| 0:01
+
| 00:01
 
| Hello Friends and Welcome to the tutorial on 'loops' in Python.
 
| Hello Friends and Welcome to the tutorial on 'loops' in Python.
  
 
|-
 
|-
−
| 0:05
+
| 00:05
 
| At the end of this tutorial, you will be able to,
 
| At the end of this tutorial, you will be able to,
  
Line 15: Line 16:
  
 
|-
 
|-
−
| 0:17
+
| 00:17
 
| Before beginning this tutorial,we would suggest you to complete the tutorial on "Getting started with for" and "Conditionals".
 
| Before beginning this tutorial,we would suggest you to complete the tutorial on "Getting started with for" and "Conditionals".
  
 
|-
 
|-
−
| 0:24
+
| 00:24
 
| Let us start our ipython interpreter.
 
| Let us start our ipython interpreter.
  
 
|-
 
|-
−
|0:28
+
|00:28
 
|Type ipython in the terminal
 
|Type ipython in the terminal
  
 
|-
 
|-
−
|  0:32
+
|  00:32
 
| We shall first begin with the while  loop.  
 
| We shall first begin with the while  loop.  
  
 
|-
 
|-
−
|  0:34
+
|  00:34
 
| The while  loop is used for repeated execution as long as a condition is  True .
 
| The while  loop is used for repeated execution as long as a condition is  True .
  
 
|-
 
|-
−
|  0:39
+
|  00:39
 
| Let us print the squares of all the odd numbers less than 10, using the  while  loop.
 
| Let us print the squares of all the odd numbers less than 10, using the  while  loop.
  
 
|-
 
|-
−
|0:45
+
|00:45
 
|Type i = 1
 
|Type i = 1
  
Line 47: Line 48:
  
 
|-
 
|-
−
| 1:19
+
| 01:19
 
| This loop prints the squares of the odd numbers below 10.
 
| This loop prints the squares of the odd numbers below 10.
  
 
|-
 
|-
−
|  1:23
+
|  01:23
 
| The while  loop, repeatedly checks if the condition is true and executes the block of code within the loop, if it is.  
 
| The while  loop, repeatedly checks if the condition is true and executes the block of code within the loop, if it is.  
  
 
|-
 
|-
−
|  1:30
+
|  01:30
 
| As with any other block in Python, the code within the  while  block is indented to the right by 4 spaces.
 
| As with any other block in Python, the code within the  while  block is indented to the right by 4 spaces.
  
 
|-
 
|-
−
|  1:41
+
|  01:41
 
| Pause the video here, try out the following exercise and resume the video.
 
| Pause the video here, try out the following exercise and resume the video.
  
 
|-
 
|-
−
| 1:48
+
| 01:48
 
| '''Write a  while  loop to print the squares of all the even''' numbers below 10.
 
| '''Write a  while  loop to print the squares of all the even''' numbers below 10.
  
 
|-
 
|-
−
| 1:55
+
| 01:55
 
| Switch to the terminal for solution.
 
| Switch to the terminal for solution.
  
 
|-
 
|-
−
|1:58
+
|01:58
 
|Type i = 2
 
|Type i = 2
  
Line 79: Line 80:
  
 
|-
 
|-
−
| 2:27
+
| 02:27
 
| Let us now solve the same problem of printing the squares of all odd numbers less than 10, using the  for  loop.  
 
| Let us now solve the same problem of printing the squares of all odd numbers less than 10, using the  for  loop.  
  
 
|-
 
|-
−
|  2:34
+
|  02:34
 
| As we know, the  for  loop iterates over a list or any other sequential data type.  
 
| As we know, the  for  loop iterates over a list or any other sequential data type.  
  
 
|-
 
|-
−
|  2:40
+
|  02:40
 
| 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.
 
| 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
+
|02:48
 
|Type for n in range within bracket 1 comma 10 comma 2 colon
 
|Type for n in range within bracket 1 comma 10 comma 2 colon
 
       print n multiply by n
 
       print n multiply by n
  
 
|-
 
|-
−
| 3:07
+
| 03:07
 
| We can see that we got the same output as before.  
 
| We can see that we got the same output as before.  
  
 
|-
 
|-
−
|  3:10
+
|  03:10
 
| Note that the lines of code are less.
 
| Note that the lines of code are less.
  
 
|-
 
|-
−
|  3:13
+
|  03:13
 
| Pause the video here, try out the following exercise and resume the video.
 
| Pause the video here, try out the following exercise and resume the video.
  
 
|-
 
|-
−
| 3:19
+
| 03:19
 
| '''Write a  for loop to print the squares of all the even''' numbers below 10.
 
| '''Write a  for loop to print the squares of all the even''' numbers below 10.
  
 
|-
 
|-
−
| 3:24
+
| 03:24
 
| Switch to the terminal
 
| Switch to the terminal
  
 
|-
 
|-
−
| 3:26
+
| 03:26
 
|Type for n in range within bracket 2 comma 10 comma 2 colon
 
|Type for n in range within bracket 2 comma 10 comma 2 colon
 
         print n multiply by n
 
         print n multiply by n
  
 
|-
 
|-
−
| 3:46
+
| 03:46
 
| Let us now look at how to use the keywords,  pass ,  break  and  continue .
 
| Let us now look at how to use the keywords,  pass ,  break  and  continue .
  
 
|-
 
|-
−
|  3:52
+
|  03:52
 
| As we already know, pass is just a syntactic filler.  
 
| As we already know, pass is just a syntactic filler.  
  
 
|-
 
|-
−
|  3:56
+
|  03:56
 
| It is used for the sake of completion of blocks, that do not have any code within them.
 
| It is used for the sake of completion of blocks, that do not have any code within them.
  
 
|-
 
|-
−
|4:02
+
|04:02
 
|Type for n in range within bracket 2 comma 10 comma 2 colon
 
|Type for n in range within bracket 2 comma 10 comma 2 colon
  
Line 141: Line 142:
  
 
|-
 
|-
−
| 4:20
+
| 04:20
 
|  break  is used to break out of the innermost loop.  
 
|  break  is used to break out of the innermost loop.  
  
 
|-
 
|-
−
|  4:24
+
|  04:24
 
| The  while loop to print the squares of all the odd numbers below 10, can be modified using the break  statement, as follows
 
| 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
+
|04:31
 
|Type = 1
 
|Type = 1
  
Line 158: Line 159:
 
     break
 
     break
 
|-
 
|-
−
|5:10
+
|05:10
 
|So we got a syntax error because 'if' is not inside the while loop
 
|So we got a syntax error because 'if' is not inside the while loop
 
  So type while True colon
 
  So type while True colon
Line 168: Line 169:
  
 
|-
 
|-
−
| 5:42
+
| 05:42
 
|  continue  is used to skip execution of the rest of the loop on this iteration and continue to the end of this iteration.
 
|  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
+
|  05:50
 
| 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.
 
| 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
+
|06:03
 
|So, in terminal, Type for n in range within bracket 1 comma 10 comma 2 colon
 
|So, in terminal, Type for n in range within bracket 1 comma 10 comma 2 colon
  
Line 184: Line 185:
  
 
|-
 
|-
−
| 6:36
+
| 06:36
 
| Now Pause the video here, try out the following exercise and resume the video.
 
| Now Pause the video here, try out the following exercise and resume the video.
  
 
|-
 
|-
−
| 6:41
+
| 06:41
 
| 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.
 
| 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
+
|  06:53
 
|  (Do not modify the range function call.)
 
|  (Do not modify the range function call.)
  
 
|-
 
|-
−
| 6:59
+
| 06:59
 
| Now  Switch to the terminal for solution.
 
| Now  Switch to the terminal for solution.
  
 
|-
 
|-
−
|7:02
+
|07:02
 
|Type for n in range within bracket 2 comma 10 comma 2 colon
 
|Type for n in range within bracket 2 comma 10 comma 2 colon
 
     if n modulo 4 colon
 
     if n modulo 4 colon
Line 207: Line 208:
  
 
|-
 
|-
−
| 7:30
+
| 07:30
 
| This brings us to the end of this tutorial.
 
| This brings us to the end of this tutorial.
  
 
|-
 
|-
−
|  7:33
+
|  07:33
 
|  In this tutorial, we have learnt to, 1. Iterate over a sequence using ``for'' and ``while'' loops.
 
|  In this tutorial, we have learnt to, 1. Iterate over a sequence using ``for'' and ``while'' loops.
 
    
 
    
 
|-
 
|-
−
|  7:38
+
|  07:38
 
| 2. Break out of loops using ``break'' statement.
 
| 2. Break out of loops using ``break'' statement.
  
 
|-
 
|-
−
|  7:42
+
|  07:42
 
| 3. Skip iterations using ``continue'' statement.
 
| 3. Skip iterations using ``continue'' statement.
  
 
|-
 
|-
−
|  7:45
+
|  07:45
 
| 4. Use the ``pass'' statement in a loop.
 
| 4. Use the ``pass'' statement in a loop.
  
 
|-
 
|-
−
| 7:49
+
| 07:49
 
| Here are some self assessment questions for you to solve
 
| Here are some self assessment questions for you to solve
  
 
|-
 
|-
−
|  7:52
+
|  07:52
 
| 1. Given  range(1 comma 4) ; Write a code to print only the number 1.  
 
| 1. Given  range(1 comma 4) ; Write a code to print only the number 1.  
  
 
|-
 
|-
−
|  8:01
+
|  08:01
 
| 2.Second one is, Which statement do you use to skip iterations. - break - pass - continue
 
| 2.Second one is, Which statement do you use to skip iterations. - break - pass - continue
  
 
|-
 
|-
−
| 8:10
+
| 08:10
 
| And the answers,
 
| And the answers,
  
 
|-
 
|-
−
|  8:12
+
|  08:12
 
| 1. First one, We can use the break statement in a for loop as,
 
| 1. First one, We can use the break statement in a for loop as,
 
''' colon colon'''
 
''' colon colon'''
  
 
|-
 
|-
−
|  8:21
+
|  08:21
 
| '''for i in range within bracket 1 comma 4 colon'''
 
| '''for i in range within bracket 1 comma 4 colon'''
  
 
|-
 
|-
−
|  8:27
+
|  08:27
 
| Then print i break
 
| Then print i break
 
   
 
   
 
|-
 
|-
−
|  8:30
+
|  08:30
 
|  And second one, In order to skip iterations,we make use of the continue  statement.
 
|  And second one, In order to skip iterations,we make use of the continue  statement.
  
 
|-
 
|-
−
| 8:37
+
| 08:37
 
| Hope you have enjoyed this tutorial and found it useful.  
 
| Hope you have enjoyed this tutorial and found it useful.  
  
 
|}
 
|}

Revision as of 15:10, 10 July 2014

Time Narration
00:01 Hello Friends and Welcome to the tutorial on 'loops' in Python.
00:05 At the end of this tutorial, you will be able to,
  1. use the for loop
  2. use the while loop
  3. Use break, continue and pass statements to play around with loops.
00:17 Before beginning this tutorial,we would suggest you to complete the tutorial on "Getting started with for" and "Conditionals".
00:24 Let us start our ipython interpreter.
00:28 Type ipython in the terminal
00:32 We shall first begin with the while loop.
00:34 The while loop is used for repeated execution as long as a condition is True .
00:39 Let us print the squares of all the odd numbers less than 10, using the while loop.
00:45 Type i = 1 
while i less than 10 colon
    print i multiply by i
    i += 2
01:19 This loop prints the squares of the odd numbers below 10.
01:23 The while loop, repeatedly checks if the condition is true and executes the block of code within the loop, if it is.
01:30 As with any other block in Python, the code within the while block is indented to the right by 4 spaces.
01:41 Pause the video here, try out the following exercise and resume the video.
01:48 Write a while loop to print the squares of all the even numbers below 10.
01:55 Switch to the terminal for solution.
01:58 Type i = 2 
while i less than 10 colon
    print i multiply by i
    i += 2
02:27 Let us now solve the same problem of printing the squares of all odd numbers less than 10, using the for loop.
02:34 As we know, the for loop iterates over a list or any other sequential data type.
02:40 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.
02:48 Type for n in range within bracket 1 comma 10 comma 2 colon 
      print n multiply by n
03:07 We can see that we got the same output as before.
03:10 Note that the lines of code are less.
03:13 Pause the video here, try out the following exercise and resume the video.
03:19 Write a for loop to print the squares of all the even numbers below 10.
03:24 Switch to the terminal
03:26 Type for n in range within bracket 2 comma 10 comma 2 colon 
        print n multiply by n
03:46 Let us now look at how to use the keywords, pass , break and continue .
03:52 As we already know, pass is just a syntactic filler.
03:56 It is used for the sake of completion of blocks, that do not have any code within them.
04:02 Type for n in range within bracket 2 comma 10 comma 2 colon 
   pass

   And Enter.
04:20 break is used to break out of the innermost loop.
04:24 The while loop to print the squares of all the odd numbers below 10, can be modified using the break statement, as follows
04:31 Type = 1

while True colon 

   print i multiply by i
   i += 2
   if i is less than 10 colon
   break
05:10 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.

05:42 continue is used to skip execution of the rest of the loop on this iteration and continue to the end of this iteration.
05:50 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.
06:03 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
06:36 Now Pause the video here, try out the following exercise and resume the video.
06:41 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.
06:53 (Do not modify the range function call.)
06:59 Now Switch to the terminal for solution.
07:02 Type for n in range within bracket 2 comma 10 comma 2 colon 
   if n modulo 4 colon
       continue
   print n multiply by n
07:30 This brings us to the end of this tutorial.
07:33 In this tutorial, we have learnt to, 1. Iterate over a sequence using ``for and ``while loops.
07:38 2. Break out of loops using ``break statement.
07:42 3. Skip iterations using ``continue statement.
07:45 4. Use the ``pass statement in a loop.
07:49 Here are some self assessment questions for you to solve
07:52 1. Given range(1 comma 4) ; Write a code to print only the number 1.
08:01 2.Second one is, Which statement do you use to skip iterations. - break - pass - continue
08:10 And the answers,
08:12 1. First one, We can use the break statement in a for loop as,

colon colon

08:21 for i in range within bracket 1 comma 4 colon
08:27 Then print i break
08:30 And second one, In order to skip iterations,we make use of the continue statement.
08:37 Hope you have enjoyed this tutorial and found it useful.

Contributors and Content Editors

Gaurav, Kavita salve, Minal, PoojaMoolya, Sneha

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