Parially cleaned up conditionals LO.

2 files changed, 80 insertions, 124 deletions

diff --git a/conditionals/script.rst b/conditionals/script.rst
index 980927f..c59f1f8 100644
--- a/conditionals/script.rst
+++ b/conditionals/script.rst
@@ -1,14 +1,20 @@
 .. Objectives
 .. ----------
 
-.. Clearly state the objectives of the LO (along with RBT level)
+.. By the end of this tutorial, you will be able to 
+
+.. * Use if/else blocks 
+.. * Use if/elif/else blocks
+.. * Use the Ternary conditional statement - C if X else Y
+
+.. to check conditions in your programs. 
+
 
 .. Prerequisites
 .. -------------
 
-..   1. Name of LO-1
-..   2. Name of LO-2
-..   3. Name of LO-3
+..   1. Basic datatypes and operators
+
      
 .. Author              : Madhu
    Internal Reviewer   : 
@@ -21,8 +27,7 @@ Script
 
 {{{ Show the slide containing the title }}}
 
-Hello friends. Welcome to this spoken tutorial on Getting started with
-strings.
+Hello friends. Welcome to this spoken tutorial on Conditionals
 
 {{{ Show the slide containing the outline }}}
 
@@ -40,10 +45,12 @@ on the terminal
 
 Whenever we have two possible states that can occur depending on a
 whether a certain condition we can use if/else construct in
-Python. Say for example we have a variable "a" which stores integers
-and we are required to find out whether the value of the variable "a"
-is an even number or an odd number. To test out conditional statements
-as an example, let us say the value of the variable "a" is 5::
+Python. 
+
+For example, say, we have a variable ``a`` which stores integers and
+we are required to find out whether ``a`` is even or odd.  an even
+number or an odd number. Let's say the value of ``a`` is 5, now.
+::
 
   a = 5
 
@@ -54,36 +61,29 @@ In such a case we can write the if/else block as::
   else:
       print "Odd"
 
-When the value of the variable "a" is divided by 2 and the remainder
-is 0 i.e. the result of the operation "a modulo 2" is 0 the condition
-"a % 2 == 0" evaluates to True, so the code within the if block gets
-executed. This means that the value of "a" is Even. 
-
-If the operation "a modulo 2" is not 0 the condition "a % 2 == 0"
-evaluates to False and hence the code block within else gets executed
-which means that the value of "a" is Odd. 
-
-Note in such a case only one of the two blocks get executed depending
-on whether the condition is True or False.
-
-There is a very important sytactic element to understand here. All the
-statements which are inside a certain code block are indented by 4
-spaces. The statement which starts a new code block after it, i.e. the
-if statement in this example ends with a colon (:). So the next
-immediate line will be inside the if block and hence indented by 4
-spaces. To come out of the code block we have to come back to the
-previous indentation level as shown in the else line here. Again the
-line following else will be in a new block so else line ends with a
-colon and the following block of code is indented by 4.
-
-As we use if/else statement when we have a condition which can take
-one of the two states, we may have conditions which can take more than
-two states. In such a scenario Python provides if/elif/else
-statements. Let us take an example. We have a variable "a" which holds
-integer values. We need to print "positive" if the value of a is
-positive, "negative" if it is negative and "zero" if the value of the
-variable "a" is 0. Let us use if/elif/else ladder for it. For the
-purposes of testing our code let us assume that the value of a is -3::
+If ``a`` is divisible by 2, i.e., the result of "a modulo 2" is 0, it
+prints "Even", otherwise it prints "Odd". 
+
+Note that in such a case, only one of the two blocks gets executed
+depending on whether the condition is ``True`` or ``False``.
+
+There is a very important sytactic element to understand here. Every
+code block begins with a line that ends with a ``:``, in this example
+the ``if`` and the ``else`` lines. Also, all the statements inside a
+code block are intended by 4 spaces. Returning to the previous
+indentation level, ends the code block. 
+
+The if/else blocks work for a condition, which can take one of two
+states. What do we do for conditions, which can take more than two
+states? 
+
+Python provides if/elif/else blocks, for such conditions. Let us take
+an example. We have a variable ``a`` which holds integer values. We
+need to print "positive" if ``a`` is positive, "negative" if
+it is negative or "zero" if it is 0. 
+
+Let us use if/elif/else ladder for it. For the purposes of testing our
+code let us assume that the value of a is -3::
 
   a = -3
 
@@ -94,18 +94,18 @@ purposes of testing our code let us assume that the value of a is -3::
   else:
       print "zero"
 
-This if/elif/else ladder is self explanatory. All the syntax and rules
-as said for if/else statements hold. The only addition here is the
-elif statement which can have another condition of its own.
+All the syntax and rules as said for if/else statements hold. The only
+addition here is the ``elif`` statement which can have another
+condition of its own.
 
-Here, exactly one block of code is executed and that block of code
-corresponds to the condition which first evaluates to True. Even if
-there is a situation where multiple conditions evaluate to True all
-the subsequent conditions other than the first one which evaluates to
-True are neglected. Consequently, the else block gets executed if and
-only if all the conditions evaluate to False.
+Here too, exactly one block of code is executed -- the block of code
+which first evaluates to ``True``. Even if there is a situation where
+multiple conditions evaluate to True all the subsequent conditions
+other than the first one which evaluates to True are neglected.
+Consequently, the else block gets executed if and only if all the
+conditions evaluate to False.
 
-Also, the else block in both if/else statement and if/elif/else is
+Also, the ``else`` block in both if/else statement and if/elif/else is
 optional. We can have a single if statement or just if/elif statements
 without having else block at all. Also, there can be any number of
 elif's within an if/elif/else ladder. For example
@@ -124,6 +124,12 @@ elif's within an if/elif/else ladder. For example
 is completely valid. Note that there are multiple elif blocks and there
 is no else block.
 
+Following is an exercise that you must do. 
+
+%% %% 
+
+Please, pause the video here. Do the exercise and then continue. 
+
 In addition to these conditional statements, Python provides a very
 convenient ternary conditional operator. Let us take the following
 example where we read the marks data from a data file which is
@@ -147,10 +153,16 @@ like score is integer of score_str is score_str is not 'AA' otherwise
 it is 0. This means that we make the scores of the students who were
 absent for the exam 0.
 
-Moving on, there are certain situations where we will have to no
-operations or statements within the block of code. For example, we
-have a code where we are waiting for the keyboard input. If the user
-enters "s" as the input we would perform some operation nothing
+Following is an exercise that you must do. 
+
+%% %%     
+
+Please, pause the video here. Do the exercise and then continue. 
+
+Moving on, there are certain situations where we will have no
+operations or statements within a block of code. For example, we have
+a code where we are waiting for the keyboard input. If the user enters
+"c", "d" or "x" as the input we would perform some operation nothing
 otherwise. In such cases "pass" statement comes very handy::
 
   a = raw_input("Enter 'c' to calculate and exit, 'd' to display the existing
@@ -167,8 +179,7 @@ otherwise. In such cases "pass" statement comes very handy::
 
 In this case "pass" statement acts as a place holder for the block of
 code. It is equivalent to a null operation. It literally does
-nothing. So "pass" statement can be used as a null operation
-statement, or it can used as a place holder when the actual code
+nothing. It can used as a place holder when the actual code
 implementation for a particular block of code is not known yet but has
 to be filled up later.
 
diff --git a/conditionals/slides.org b/conditionals/slides.org
index 5d2ce93..084fa83 100644
--- a/conditionals/slides.org
+++ b/conditionals/slides.org
@@ -18,7 +18,7 @@
 #+LaTeX_HEADER:  commentstyle=\color{red}\itshape, stringstyle=\color{darkgreen},
 #+LaTeX_HEADER:  showstringspaces=false, keywordstyle=\color{blue}\bfseries}
 
-#+TITLE:    Accessing parts of arrays
+#+TITLE:    Conditionals
 #+AUTHOR:    FOSSEE
 #+EMAIL:     
 #+DATE:    
@@ -30,81 +30,26 @@
 #+OPTIONS:   TeX:t LaTeX:nil skip:nil d:nil todo:nil pri:nil tags:not-in-toc
 
 * Outline
-  - Manipulating one and multi dimensional arrays
-  - Access and change individual elements 
-  - Access and change rows and columns 
-  - Slicing and striding on arrays to access chunks 
-  - Read images into arrays and manipulations
-* Sample Arrays
-  #+begin_src python
-    In []: A = array([12, 23, 34, 45, 56])
-    
-    In []: C = array([[11, 12, 13, 14, 15],
-                      [21, 22, 23, 24, 25],
-                      [31, 32, 33, 34, 35],
-                      [41, 42, 43, 44, 45],
-                      [51, 52, 53, 54, 55]])
-    
-  #+end_src
+
 * Question 1
-  Change the last column of ~C~ to zeroes. 
+
 * Solution 1
   #+begin_src python
-    In []:  C[:, -1] = 0
-  #+end_src
-* Question 2
-  Change ~A~ to ~[11, 12, 13, 14, 15]~. 
-* Solution 2
-  #+begin_src python
-    In []:  A[:] = [11, 12, 13, 14, 15]
-  #+end_src
-* squares.png
-  #+begin_latex
-    \begin{center}
-      \includegraphics[scale=0.6]{squares}    
-    \end{center}
-  #+end_latex
-* Question 3
-  - obtain ~[22, 23]~ from ~C~. 
-  - obtain ~[11, 21, 31, 41]~ from ~C~. 
-  - obtain ~[21, 31, 41, 0]~.   
-* Solution 3
-  #+begin_src python
-    In []:  C[1, 1:3]
-    In []:  C[0:4, 0]
-    In []:  C[1:5, 0]
-  #+end_src
-* Question 4
-  Obtain ~[[23, 24], [33, -34]]~ from ~C~
-* Solution 4
-  #+begin_src python
-    In []:  C[1:3, 2:4]
-  #+end_src
-* Question 5
-  Obtain the square in the center of the image
-* Solution 5
-  #+begin_src python
-    In []: imshow(I[75:225, 75:225])
-  #+end_src
-* Question 6
-  Obtain the following
-  #+begin_src python
-    [[12, 0], [42, 0]]
-    [[12, 13, 14], [0, 0, 0]]
+
   #+end_src
 
-* Solution 6
+* ~if/elif~ ladder
   #+begin_src python
-    In []: C[::3, 1::3]
-    In []: C[::4, 1:4]
+    if user == 'admin':
+        # Do admin operations
+    elif user == 'moderator':
+        # Do moderator operations
+    elif user == 'client':
+        # Do customer operations
   #+end_src
+
 * Summary
-  You should now be able to --
-  - Manipulate 1D \& Multi dimensional arrays
-      - Access and change individual elements 
-      - Access and change rows and columns 
-      - Slice and stride on arrays
-  - Read images into arrays and manipulate them.
+
 * Thank you!
 #+begin_latex
   \begin{block}{}