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author | bhanu |

Thu, 11 Nov 2010 02:02:06 +0530 | |

changeset 475 | 2e0b89c0eeb4 |

parent 474 | f137f3e036d9 |

child 476 | cb587df417bd |

Laguage check Done for `getting started with arrays`

--- a/getting-started-with-arrays/script.rst Thu Nov 11 00:24:11 2010 +0530 +++ b/getting-started-with-arrays/script.rst Thu Nov 11 02:02:06 2010 +0530 @@ -20,6 +20,7 @@ .. Author: Anoop Jacob Thomas <anoop@fossee.in> Internal Reviewer : Puneeth External Reviewer : + Language Reviewer : Bhanukiran Checklist OK? : <put date stamp here, if OK> [2010-10-05] =========================== @@ -34,17 +35,17 @@ {{{ switch to next slide, outline slide }}} -In this tutorial, we will learn about arrays, we will learn how to convert -a list into an array array operations and also why an array is preferred -over lists. +In this tutorial, we will learn about the data structure called an array, how to convert +a list into an array, operations on arrays and also why an array is preferred +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 -type, either all integers, or strings, or float, and not a mix. +heterogeneous data elements, that is, they can have only one type of data +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. @@ -52,8 +53,9 @@ 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, -because of the same type of data in arrays. +Arrays of a given length are comparatively much faster in mathematical +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? @@ -77,7 +79,7 @@ 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 @@ -112,7 +114,7 @@ .. #[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. :: @@ -120,7 +122,7 @@ .. #[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. @@ -154,13 +156,13 @@ {{{ 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 ?] @@ -200,8 +202,8 @@ 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 +Well, we would expect an error as it has been previously mentioned that arrays handle +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, :: @@ -218,8 +220,8 @@ {{{ 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. +all the elements have been implicitly type casted as strings, though our +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? ;)] @@ -229,25 +231,26 @@ .. #[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 -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 +Now let us see how to create an identity matrix of a given size, that is a +two-dimensional array in which all the diagonal elements are ones and rest of the +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 -with all the diagonal elements as one and the rest of the elements as zero. +As you can see the identity function returned a three by three square matrix +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 -want to create, and it generates an array with all elements zero. +``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 as zeros. {{{ switch to the next slide, problem statement of solved exercise 1 }}}