--- a/getting-started-with-arrays/script.rst Wed Oct 13 11:15:37 2010 +0530
+++ b/getting-started-with-arrays/script.rst Wed Oct 13 12:52:11 2010 +0530
@@ -11,29 +11,56 @@
.. * array operations
.. + =+ - * /=
+.. Objectives
+.. ----------
+
+.. Clearly state the objectives of the LO (along with RBT level)
+
+.. Prerequisites
+.. -------------
+
+.. 1. Name of LO-1
+.. 2. Name of LO-2
+.. 3. Name of LO-3
+
+.. Author: Anoop Jacob Thomas <anoop@fossee.in>
+ Internal Reviewer : Puneeth
+ External Reviewer :
+ Checklist OK? : <put date stamp here, if OK> [2010-10-05]
+
===========================
Getting started with Arrays
===========================
+.. #[Puneeth: Prerequisites and Objectives are missing. Fill them in]
+
{{{ show the welcome slide }}}
Welcome to the spoken tutorial on getting started with arrays.
{{{ switch to next slide, outline slide }}}
-In this tutorial, we will learn about arrays, how to convert a list
-into an array and also why an array is preferred over lists. And array
-operations.
+In this tutorial, we will learn about arrays, how to convert a list into an
+array and also why an array is preferred over lists. And array operations.
+
+.. #[Puneeth: Fix the grammar above.]
{{{ switch to next slide on overview of array }}}
-Arrays are homogeneous data structures, unlike lists, arrays cannot
-have heterogeneous data elements, that is, it can have only one type
-of data type, either all integers, or strings, or float, and not a
-mix.
+Arrays are homogeneous data structures, unlike lists, arrays cannot have
+heterogeneous data elements, that is, it can have only one type of data
+type, either all integers, or strings, or float, and not a mix.
+
+.. #[Puneeth: Use multiple short sentences, rather than one long sentence
+ I would've written something like this.
-Arrays are really fast in mathematical operations when compared to
-lists, it is at least 80 to 100 times faster than lists.
+ Unlike lists, arrays are homogeneous data structures. They can have only
+ type of data, ....]
+
+Arrays are really fast in mathematical operations when compared to lists,
+it is at least 80 to 100 times faster than lists.
+
+.. #[Puneeth: For what size of an array is that the comparison?
{{{ switch to the next slide, creating arrays }}}
@@ -42,39 +69,63 @@
I am assuming that you have your IPython interpreter running with the
``-pylab`` option, so that you have the required modules loaded.
+.. #[Puneeth: 'I am assuming' doesn't sound right. Ask them to open if it
+.. is not open?]
+
To create an array we will use the function ``array()`` as,
+
::
a1 = array([1,2,3,4])
-Notice that here we created a one dimensional array. Also notice the
-object we passed to create an array. Now let us see how to create a
-two dimensional array. Pause here and try to do it yourself before
-looking at the solution.
+Notice that here we created a one dimensional array. Also notice the object
+we passed to create an array. Now let us see how to create a two
+dimensional array. Pause here and try to do it yourself before looking at
+the solution.
+
+.. #[Puneeth: I don't think this question can be solved by an average
+.. viewer. Questions during the tutorial, should generally be to re-iterate
+.. concepts learnt? ]
+
+.. #[Puneeth: Also, you didn't even point out that we are converting a
+.. list, using the ``array`` function. Bring the later section about
+.. converting a list, here. A separate section is not necessary, IMHO.]
This is how we create two dimensional arrays.
+
::
a2 = array([[1,2,3,4],[5,6,7,8]])
+.. #[Puneeth: Again, you could explain a bit about the fact that we are
+.. converting a list of lists.]
+
Let us see an easy method of creating an array with elements 1 to 8.
+
::
ar = arange(1,9)
+.. #[Puneeth: say, creating the same array as before. for some time I got
+.. confused .]
+
And it created a single dimensional array of elements from 1 to 8.
+
::
print ar
-And how can we make it a two dimensional array of order 2 by 4. Pause
-here and try to do it yourself, try ``ar.tab`` and find a suitable
-method for that.
+.. #[Puneeth: be consistent with voice. say, we obtained... or something.]
+
+And how can we make it a two dimensional array of order 2 by 4. Pause here
+and try to do it yourself, try ``ar.tab`` and find a suitable method for
+that.
{{{ switch to next slide, reshape() method }}}
-We can use the function ``reshape()`` for that purpose and it can be
-done as,
+We can use the function ``reshape()`` for that purpose and it can be done
+as,
+
::
ar.reshape(2,4)
@@ -84,14 +135,15 @@
{{{ switch to next slide, creating array from list}}}
Now, let us see how to convert a list object to an array. As you have
-already seen, in both of the previous statements we have passed a
-list, so creating an array can be done so, first let us create a list
-``l1``
+already seen, in both of the previous statements we have passed a list, so
+creating an array can be done so, first let us create a list ``l1``
+
::
l1 = [1,2,3,4]
-Now we can convert the list to an array as,
+Now we can convert the list to an array as,
+
::
a3 = array(l1)
@@ -101,70 +153,96 @@
Create a three dimensional array of the order (2,2,4).
+.. #[Puneeth: s/order/shape or size ?]
+
{{{ switch to the next slide, shape of an array }}}
To find the shape of an array we can use the object ``.shape``, let us
check the shape of the arrays we have created so far,
+
+.. #[Puneeth: s/object/method ?]
+
::
a1.shape
-``a1.shape`` object is a tuple, and since a1 is a single dimensional
-array, it returned a tuple (4,).
+``a1.shape`` object is a tuple, and since a1 is a single dimensional array,
+it returned a tuple (4,).
+
+.. #[Puneeth: first show a 2D array, so that it becomes easier to explain.
+.. Also, the word ``tuple`` need not be mentioned. ]
{{{ switch to the next slide, unsolved exercise 2 }}}
Find out the shape of the other arrays that we have created.
+.. #[Puneeth: solution missing.]
+
{{{ Array can have only a single type of data }}}
-Now let us try to create a new array with a mix of elements and see
-what will happen,
+.. #[Puneeth: I guess, this whole section can be skipped. If you want to
+.. keep this, just briefly mention that arrays are homogeneous in the
+.. intro, don't explain it there.]
+
+Now let us try to create a new array with a mix of elements and see what
+will happen,
+
::
a4 = array([1,2,3,'a string'])
-Well, we expected an error as previously I said that an array can have
-only homogeneous elements, but it didn't give an error. Let us check
-the values in the new array created. In your IPython terminal type,
+Well, we expected an error as previously I said that an array can have only
+homogeneous elements, but it didn't give an error. Let us check the values
+in the new array created. In your IPython terminal type,
::
a4
-Did you notice it,
+Did you notice it,
{{{ switch to next slide, implicit type casting }}}
-{{{ highlight all the array elements one by one using mouse
-movements }}}
+.. #[Puneeth: typecasting may be unnecessary. (Also too advanced?) an
+.. average guy wouldn't use arrays with strings.]
+
+.. #[Puneeth: You may want to mention that float is the default dtype.]
-all the elements have been implicitly type casted as string, though
-our first three elements were integers.
+{{{ highlight all the array elements one by one using mouse movements }}}
+
+all the elements have been implicitly type casted as string, though our
+first three elements were integers.
+
+.. #[Puneeth: when I type a4 it says some ``dtype`` etc. I don't understand
+.. what it is, can you explain? ;)]
{{{ switch to the next slide, identity & zeros methods }}}
-An identity matrix is a square matrix in which all the diagonal
-elements are one and rest of the elements zero. We can create an
-identity matrix using the method ``identity()``.
+.. #[Puneeth: something needs to motivate this. why are we suddenly talking
+.. of an identity matrix?]
+
+An identity matrix is a square matrix in which all the diagonal elements
+are one and rest of the elements zero. We can create an identity matrix
+using the method ``identity()``.
The function ``identity()`` takes an integer argument,
+
::
identity(3)
-As you can see the identity method returned a three by three square
-array with all the diagonal elements as one and the rest of the
-elements as zero.
+As you can see the identity method returned a three by three square array
+with all the diagonal elements as one and the rest of the elements as zero.
-``zeros()`` function accepts a tuple, which is the order of the array
-we want to create, and it generates an array with all elements zero.
+.. #[Puneeth: You say array here, matrix there -- it's a bit messed up.
+.. Clarify, explicitly.]
-{{{ switch to the next slide, problem statement of the solved exercise
-1 }}}
+``zeros()`` function accepts a tuple, which is the order of the array we
+want to create, and it generates an array with all elements zero.
-Let us creates an array of the order four by five with all the
-elements zero. We can do it using the method zeros,
-::
+{{{ switch to the next slide, problem statement of solved exercise 1 }}}
+
+Let us creates an array of the order four by five with all the elements
+zero. We can do it using the method zeros, ::
zeros((4,5))
@@ -216,8 +294,7 @@
a
-We can use all the mathematical operations with arrays, Now let us try
-this
+We can use all the mathematical operations with arrays, Now let us try this
::
a1 = array([1,2,3,4])
@@ -229,20 +306,25 @@
a1 * a2
-Returns an array with element by element multiplication, notice that
-it does not perform matrix multiplication.
+Returns an array with element by element multiplication, notice that it
+does not perform matrix multiplication.
{{{ switch to next slide, summary slide }}}
-So this brings us to the end of this tutorial, in this tutorial we
-covered basics of arrays, how to create an array, converting a list to
-an array, basic array operations etc.
+So this brings us to the end of this tutorial, in this tutorial we covered
+basics of arrays, how to create an array, converting a list to an array,
+basic array operations etc.
+
+.. #[Puneeth: s/how to create an array/creating an array]
{{{ switch to next slide, thank you }}}
Thank you!
-.. Author: Anoop Jacob Thomas <anoop@fossee.in>
- Reviewer 1:
- Reviewer 2:
- External reviewer:
+..
+ Local Variables:
+ mode: rst
+ indent-tabs-mode: nil
+ sentence-end-double-space: nil
+ fill-column: 75
+ End: