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Diffstat (limited to 'loops/script.rst')
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1 files changed, 185 insertions, 68 deletions
diff --git a/loops/script.rst b/loops/script.rst index 421794f..75ae0ef 100644 --- a/loops/script.rst +++ b/loops/script.rst @@ -25,26 +25,49 @@ Script ------ -{{{ Show the slide containing title }}} +.. L1 -Hello Friends. Welcome to the tutorial on loops in Python. +{{{ Show the first slide containing title, name of the production +team along with the logo of MHRD }}} -{{{ Show the outline slide }}} +.. R1 -In this tutorial, we shall look at ``while`` and ``for`` loops. We -shall then look at how to break out of them, or skip some iterations -in loops. +Hello Friends and Welcome to the tutorial on 'loops' in Python. -.. #[[Anoop: for loop is a pre-requisite and has been already covered, - so i think our emphasize can be on while loops]] +.. L2 -.. #[[punch: I think, we should have both of them. It gives a better -.. context and comparison.] +{{{ Show the objectives slide }}} + +.. R2 + +At the end of this tutorial, you will be able to, + + 1. use the ``for`` loop + #. use the ``while`` loop + #. Use ``break``, ``continue`` and ``pass`` statements to play around + with loops. + +.. L3 + +{{{ Switch to the pre-requisite slide }}} + +.. R3 + +Before beginning this tutorial,we would suggest you to complete the +tutorial on "Getting started with for" and "Conditionals". + +.. R4 + +Let us start our ipython interpreter. + +.. L4 {{{ switch to the ipython terminal }}} +:: -We have an ``ipython`` terminal, that we shall use through out this -tutorial. + ipython + +.. R5 We shall first begin with the ``while`` loop. The ``while`` loop is used for repeated execution as long as a condition is ``True``. @@ -52,13 +75,16 @@ used for repeated execution as long as a condition is ``True``. Let us print the squares of all the odd numbers less than 10, using the ``while`` loop. +.. L5 :: - i = 1 + i = 1 + + while i<10: + print i*i + i += 2 - while i<10: - print i*i - i += 2 +.. R6 This loop prints the squares of the odd numbers below 10. @@ -67,24 +93,36 @@ executes the block of code within the loop, if it is. As with any other block in Python, the code within the ``while`` block is indented to the right by 4 spaces. -{{{ switch to next slide }}} +Pause the video here, try out the following exercise and resume the video. + +.. L6 -Following is an exercise that you must do. +.. L7 -%%1%% Write a ``while`` loop to print the squares of all the even -numbers below 10. +{{{ Show slide with exercise 1 }}} -Please, pause the video here. Do the exercise and then continue. +.. R7 -{{{ switch to next slide after a seconds break}}} + Write a ``while`` loop to print the squares of all the even + numbers below 10. +.. R8 + +Switch to the terminal for solution. + +.. L8 + +{{{continue from paused state}}} +{{{ Switch to the terminal }}} :: - i = 2 + i = 2 + + while i<10: + print i*i + i += 2 - while i<10: - print i*i - i += 2 +.. R9 Let us now solve the same problem of printing the squares of all odd numbers less than 10, using the ``for`` loop. As we know, the ``for`` @@ -92,26 +130,44 @@ loop iterates over a list or any other sequential data type. 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. +.. L9 :: - for n in range(1, 10, 2): - print n*n + for n in range(1, 10, 2): + print n*n + +.. R10 + +We can see that we got the same ouput as before.Note that the lines of code +are less. + +Pause the video here, try out the following exercise and resume the video. -Following is an exercise that you must do. +.. L10 -{{{ switch to next slide }}} +.. L11 -%%2%% Write a ``for`` loop to print the squares of all the even -numbers below 10. +{{{ Show slide with exercise 2 }}} -Please, pause the video here. Do the exercise and then continue. +.. R11 -{{{ switch to next slide after a seconds break }}} + Write a ``for`` loop to print the squares of all the even + numbers below 10. +.. R12 + +Switch to the terminal for solution. + +.. L12 + +{{{continue from paused state}}} +{{{ Switch to the terminal }}} :: - for n in range(2, 10, 2): - print n*n + for n in range(2, 10, 2): + print n*n + +.. R13 Let us now look at how to use the keywords, ``pass``, ``break`` and ``continue``. @@ -120,67 +176,128 @@ As we already know, ``pass`` is just a syntactic filler. It is used for the sake of completion of blocks, that do not have any code within them. +.. L13 :: - for n in range(2, 10, 2): - pass + for n in range(2, 10, 2): + pass + +.. R14 ``break`` is used to break out of the innermost loop. The ``while`` loop to print the squares of all the odd numbers below 10, can be modified using the ``break`` statement, as follows + +.. L14 :: - i = 1 + i = 1 - while True: - print i*i - i += 2 - if i<10: - break + while True: + print i*i + i += 2 + if i<10: + break + +.. R15 ``continue`` is used to skip execution of the rest of the loop on this iteration and continue to the end of this iteration. -.. #[[Anoop: should add slides for break, continue, pass]] - Say, 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. :: +follows. + +.. L15 +:: - for n in range(1, 10, 2): - if n%3 == 0: - continue - print n*n + for n in range(1, 10, 2): + if n%3 == 0: + continue + print n*n + +.. R16 +Pause the video here, try out the following exercise and resume the video. + +.. L16 + +.. L17 -Following is an exercise that you must do. +{{{ Show slide with exercise 3 }}} -{{{ switch to next slide }}} +.. R17 -%%3%%Using the ``continue`` keyword modify the ``for`` loop, with the -``range(2, 10, 2)``, to print the squares of even numbers below 10, to -print the squares of only multiples of 4. +Using the ``continue`` keyword modify the ``for`` loop, with the +``range(2, 10, 2)``, to print the squares of even numbers below 10, +which are multiples of 4. +(Do not modify the range function call.) -Please, pause the video here. Do the exercise and then continue. +.. R18 -{{{ switch to next slide after a seconds break}}} +Switch to the terminal for solution. +.. L18 + +{{{continue from paused state}}} +{{{ Switch to the terminal }}} :: - for n in range(2, 10, 2): - if n%4: - continue - print n*n + for n in range(2, 10, 2): + if n%4: + continue + print n*n + +.. L19 {{{ Show summary slide }}} -That brings us to the end of this tutorial. In this tutorial, we have -learnt about looping structures in Python and the use of the keywords -``pass``, ``break`` and ``continue``. +.. R19 + +This brings us to the end of this tutorial. In this tutorial, we have learnt to, + + 1. Iterate over a sequence using ``for'' and ``while'' loops. + #. Break out of loops using ``break'' statement. + #. Skip iterations using ``continue'' statement. + #. Use the ``pass'' statement in a loop. + +.. L20 + +{{{Show self assessment questions slide}}} + +.. R20 + +Here are some self assessment questions for you to solve + + 1. Given ``range(1,4)``; Write a code to print only the number 1. + + 2. Which statement do you use to skip iterations. + - break + - pass + - continue + +.. L21 + +{{{solution of self assessment questions on slide}}} + +.. R21 + +And the answers, + +1. We can use the break statement in a for loop as, + +:: + for i in range(1, 4): + print i + break + +2. In order to skip iterations,we make use of the ``continue`` statement. + +.. L22 -{{{ Show the "sponsored by FOSSEE" slide }}} +{{{ Show the thankyou slide }}} -This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India +.. R22 -Hope you have enjoyed and found it useful. +Hope you have enjoyed this tutorial and found it useful. Thank you! |