st-scripts: comparison getting-started-with-arrays/script.rst

equal deleted inserted replaced

-:8249ae9d570a
+:88a01948450d
 ..   #. getting started with lists.
 ..  Author: Anoop Jacob Thomas <anoop@fossee.in>
 Internal Reviewer   : Puneeth
 External Reviewer   :
-Checklist OK?       : <put date stamp here, if OK> [2010-10-05]
+Language Reviewer   : Bhanukiran
+Checklist OK?       : <11-11-2010,Anand, OK > [2010-10-05]
 ===========================
 Getting started with Arrays
 ===========================
 Welcome to the spoken tutorial on getting started with arrays.
 {{{ switch to next slide, outline slide }}}
-In this tutorial, we will learn about arrays, we will learn how to convert
+In this tutorial, we will learn about the data structure called an array, how to convert
-a list into an array array operations and also why an array is preferred
+a list into an array, operations on arrays and also why an array is preferred
-over lists.
+to lists.
 .. #[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
+heterogeneous data elements, that is, they can have only one type of data
-type, either all integers, or strings, or float, and not a mix.
+as their entries, be them all integers, strings, or maybe floats, but not a mix.
 .. #[Puneeth: Use multiple short sentences, rather than one long sentence
 I would've written something like this.
 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,
+Arrays of a given length are comparatively much faster in mathematical
-because of the same type of data in arrays.
+operations than lists of the same length, because of the fact that they are
+homogeneous data structures.
 .. #[Puneeth: For what size of an array is that the comparison?
 {{{ switch to the next slide, creating arrays }}}
 ::
 a1 = array([1,2,3,4])
-Notice that here we created a one dimensional array. Also notice the object
+Notice that we created a one dimensional array here. Also notice the object
 we passed to create an array. We passed a list 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.
 ar = arange(1,9)
 .. #[Puneeth: say, creating the same array as before. for some time I got
 .. confused .]
-And we obtained a single dimensional array with elements from 1 to 8.
+And we obtained a one dimensional array with elements from 1 to 8.
 ::
 print ar
 .. #[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 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 }}}
 a3 = array(l1)
 {{{ switch to the next slide, problem statement of unsolved exercise 1 }}}
-Create a three dimensional array of the order (2,2,4).
+Create a three dimensional array of the shape (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
+To find the shape of an array we can use the method ``.shape``, let us
 check the shape of the arrays we have created so far,
 .. #[Puneeth: s/object/method ?]
 ::
 ::
 a4 = array([1,2,3,'a string'])
-Well, we expected an error as previously I said that an array can have only
+Well, we would expect an error as it has been previously mentioned that arrays handle
-homogeneous elements, but it didn't give an error. Let us check the values
+elements with the same datatype, but it didn't raise an error. Let us check the values
 in the new array created. In your IPython terminal type,
 ::
 a4
 .. #[Puneeth: You may want to mention that float is the default dtype.]
 {{{ highlight all the array elements one by one using mouse movements }}}
-all the elements have been implicitly type casted as string, though our
+all the elements have been implicitly type casted as strings, though our
-first three elements were integers.
+first three elements were meant to be 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 }}}
 .. #[Puneeth: something needs to motivate this. why are we suddenly talking
 .. of an identity matrix?]
-Now let us see how to create identity matrix, an identity matrix is a
+Now let us see how to create an identity matrix of a given size, that is a
-square matrix in which all the diagonal elements are one and rest of the
+two-dimensional array  in  which all the diagonal elements are ones and rest of the
-elements zero. We can create an identity matrix using the method
+elements are zeros. We can create an identity matrix using the function
 ``identity()``.
-The function ``identity()`` takes an integer argument,
+The function ``identity()`` takes an integer argument which specifies the
+size of the desired matrix,
 ::
 identity(3)
-As you can see the identity method returned a three by three square matrix
+As you can see the identity function returned a three by three square matrix
-with all the diagonal elements as one and the rest of the elements as zero.
+with all the diagonal elements as ones and the rest of the elements as zeros.
 .. #[Puneeth: You say array here, matrix there -- it's a bit messed up.
 .. Clarify, explicitly.]
-``zeros()`` function accepts a tuple, which is the order of the array we
+``zeros()`` function accepts a tuple, which is the order of the array that we
-want to create, and it generates an array with all elements zero.
+want to create, and it generates an array with all elements as 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, ::

changeset 521	88a01948450d
parent 476	cb587df417bd