Python/C3/Getting-started-with-arrays/English-timed - Revision history

PoojaMoolya at 06:21, 27 March 2017

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PoojaMoolya at 11:49, 20 February 2017

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Gaurav at 10:18, 3 September 2014

2014-09-03T10:18:26Z

Gaurav at 09:12, 10 July 2014

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Sneha at 09:22, 18 March 2013

2013-03-18T09:22:28Z

Sneha at 07:13, 18 March 2013

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Sneha at 07:11, 18 March 2013

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Sneha at 06:57, 18 March 2013

2013-03-18T06:57:54Z

Minal: Created page with '{| border=1 !Visual Cue !Narration |- | 0:01 | Hello friends and welcome to the spoken tutorial on 'Getting started with arrays'. |- | 0:06 | At the end of this tutorial, you wi…'

2013-01-02T11:02:36Z

Created page with '{| border=1 !Visual Cue !Narration |- | 0:01 | Hello friends and welcome to the spoken tutorial on 'Getting started with arrays'. |- | 0:06 | At the end of this tutorial, you wi…'

New page

{| border=1
!Visual Cue
!Narration
|-
| 0:01
| Hello friends and welcome to the spoken tutorial on 'Getting started with arrays'.

|-
| 0:06
| At the end of this tutorial, you will be able to,

# Create arrays using data.
# Create arrays from lists.
# Perform basic array operations.
# Create identity matrix.
# Use functions zeros(), zeros underscore like(), ones(), ones underscore like().

|-
| 0:26
| So Before beginning this tutorial,we would suggest you to complete the tutorial on "Getting started with Lists".

|-
| 0:35
| Arrays are homogeneous data structures.

|-
| 0:39
|Unlike lists, arrays cannot have heterogeneous data elements.

|-
| 0:45
|They can have only one type of data as their entries, be them all integers, strings, or maybe floats, but not a mix.

|-
| 0:55
|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.

|-
| 1:07
|Let us see how to create arrays.

|-
| 1:11
| Run your IPython interpreter with <tt>space hypen pylab</tt> option, to load the required modules to work with arrays.

|-
|1:21
|So type ipyhton space hypen pylab

|-
| 1:28
| To create an array we will use the function <tt>array()</tt> as,a1 = array within brackets square brackets 1 comma 2 comma 3 comma 4

|-
| 1:45
| Notice that we created a one dimensional array here.

|-
| 1:49
| Also notice that the object we passed to create an array is a list.

|-
| 1:54
|Now let us see how to create a two dimensional array.

|-
| 1:58
|We create two dimensional array by converting a list of lists to an array as,
a2 = array within brackets within square brackets 1 comma 2 comma 3 comma 4 comma then again within square brackets 5 comma 6 comma 7 comma 8 and hit enter.

|-
| 2:38
| Now let us use <tt>arange()</tt> function to create the same array as before.

|-
|2:45
|For that type ar = arange within bracket 1 comma 9 and hit enter,so type
print ar to get the output.

|-
| 3:02
| So now, As you can see, we obtained a one dimensional array with elements from 1 to 8.

|-
| 3:12
|Now can we make it a two dimensional array of order 2 by 4? Yes,we can.

|-
| 3:20
|For this we will have to use the function <tt>reshape()</tt>,

|-
|3:24
|So type ar.reshape brackets 2 comma 4 and hit enter

|-
|3:33
|So type ar.reshape within brackets 4 comma 2
then ar = ar dot reshape within brackets 2,4

|-
| 3:55
| Hence,we got our two-dimensional array.

|-
| 3:58
|Now, let us see how to convert a list object to an array.

|-
| 4:02
|We define a list,say l1

|-
|4:07
|So type l1 = within square brackets 1 comma 2 comma 3 comma 4 and hit enter

|-
| 4:16
| Now to convert this list to an array,we use the array function as, a3 = array within brackets l1

|-
| 4:30
| To find the shape of an array we can use the method <tt>dot shape</tt>,

|-
| 4:36
|let us check the shape of the arrays we have created so far,

|-
| 4:44
| <tt>a2 dot shape</tt> object is a tuple, and it returned a tuple (2 comma 4).

|-
| 4:52
|A tuple is nothing but an ordered list of elements.

|-
| 4:56
|So Pause the video here, try out the following exercise and resume the video.

|-
| 5:12
| Find out the shape of the other arrays i.e. a1 comma a3 comma ar that we have created.

|-
|5:22
|It can be done as
a1 dot shape
a3 dot shape
ar dot shape in the terminal

|-
| 5:37
| Now let us try to create a new array with a mix of elements and see what will happen,

|-
|5:45
|So type a4 = array within brackets then square bracket 1 comma 2 comma 3 comma and single quote a string and hit enter

|-
| 6:07
| 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.

|-
| 6:16
|Let us check the values in the new array created.

|-
| 6:19
|So Type a4 in the terminal,

|-
| 6:27
| Did you notice it, all the elements have been implicitly type casted as strings, though our first three elements were meant to be integers.

|-
| 6:37
| Also,if you have noticed,we got something like 'dtype S8' in the output.

|-
| 6:44
| dtype is nothing but the datatype which is the minimum type required to hold the objects in the sequence.

|-
| 6:52
| Let us now move on to study functions like zeros() function and ones() function.

|-
|6:59
|For this ,we will have to create a matrix.

|-
|7:02
|let us see how to create an identity matrix of a given size, this is a two-dimensional array in which all the diagonal elements are ones and rest of the elements are zeros.

|-
| 7:13
|We can create an identity matrix using the function <tt>identity()</tt>.

|-
| 7:18
|The function <tt>identity()</tt> takes an integer argument which specifies the size of the desired matrix,

|-
| 7:27
| 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 zeros.

|-
|7:43
|So type identity within brackets 3

|-
| 7:48
|<tt>zeros()</tt> 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.

|-
| 7:59
|Let us create an array of the order four by five with all the elements zero.

|-
|8:06
| We can do it using the method zeros(),

|-
|8:10
|So type zeros within brackets then again in bracket 4 comma 5 and hit enter

|-
| 8:21
| Notice that we passed a tuple to the function zeros.

|-
| 8:25
|Pause the video here, try out the following exercise and resume the video.

|-
|8:33
|So now we learnt two functions identity and zeros

|-
| 8:38
| '''Find out about the functions'''

|-
| 8:41
| zeros underscore like()

|-
| 8:43
| ones()

|-
| 8:44
| ones underscore like()

|-
| 8:48
| Try the following, first check the value of a1,

|-
| 8:52
| We see that <tt>a1</tt> is a single dimensional array,

|-
|8:56
|So type a1 and hit enter

|-
| 9:01
| So next now try a1 into 2

|-
|9:05
|So type a1 into 2

|-
| 9:09
| It returned a new array with all the elements multiplied by 2.

|-
| 9:13
|Now let us again check the contents of a1

|-
| 9:19
| note that the value of a1 still remains the same.

|-
|9:23
|Similarly with addition,so type a1 plus 2 and hit enter and then type a1

|-
|9:36
| it returns a new array, with all the elements summed with two.

|-
|9:41
|But again notice that the value of a1 has not been changed.

|-
|9:46
|You may change the value of a1 by simply assigning the newly returned array as,a1 space plus=2

|-
| 10:03
| Notice the change in elements of a by typing 'a' so type a and hit enter

|-
|10:13
|so type a1 to get the output

|-
| 10:18
| We can use all the mathematical operations with arrays,

|-
| 10:22
| Now let us try this a1 = array within brackets square brackets 1 comma 2 comma 3 comma 4
and hit enter

|-
|10:45
|then a2 = array within brackets square brackets 1 comma 2 comma 3 comma 4
then type a1 + a2
and hit enter

|-
| 11:07
| This returns an array with element by addition

|-
|11:15
|So try out a1 into a2

|-
| 11:23
| a1 into a2 returns an array with element by element multiplication,

|-
|11:31
|And notice that it does not perform matrix multiplication.

|-
| 11:37
| This brings us to the end of the end of this tutorial.

|-
| 11:41
|In this tutorial, we have learnt to,
1. Create an array using the <tt>array()</tt> function.

|-
| 11:46
| 2. Convert a list to an array.

|-
| 11:49
| 3. Perform some basic operations on arrays like addition,multiplication.

|-
| 11:53
| 4. Use functions like - .shape - arrange() - .reshape - zeros() & zeros underscore like() - ones() & ones underscore like()

|-
| 12:05
| Here are some self assessment questions for you to solve

|-
| 12:09
|1.First one, <tt><nowiki>x = array within brackets square bracket 1 comma 2 comma 3 comma square bracket 5 comma 6 comma 7</nowiki></tt> is a valid statement

|-
|12:23
| So IS True or False?

|-
| 12:27
| 2. What does the <tt>ones underscore like()</tt> function do?

|-
| 12:31
| A. Returns an array of ones with the same shape and type as a given array.

|-
| 12:37
|B. Return a new array of given shape and type, filled with ones.

|-
| 12:43
| Now Read the statements and answer,

|-
| 12:47
| Only statement A is correct.

|-
| 12:49
| Only statement B is correct.

|-
| 12:51
| Both statement A and B are correct.

|-
| 12:53
| Both statement A and B are incorrect.

|-
| 12:56
| So And the answers,

|-
| 12:59
|1. The answer is False.

|-
| 13:02
| The correct way would be to assign the elements as a list of lists and then convert it to an array

|-
|13:10
|Type <nowiki>x = array within brackets square brackets 1 comma 2 comma 3 comma square brackets 5 comma 6 comma 7</nowiki>

|-
|13:21
| 1. The function <tt>ones underscores like()</tt> returns an array of ones with the same shape and type as a given array.

|-
| 13:29
| Hope you have enjoyed this tutorial and found it useful.

|-
|13:31
|Thank you!

|}

@@ Line 247: / Line 247: @@
 |-
 | 08:43
-| ones()
+| ones(), ones underscore like()
-−
-|-
-| 08:44
-| ones underscore like()
 |-
@@ Line 344: / Line 340: @@
 |-
 | 11:41
-|In this tutorial, we have learnt to,
+|In this tutorial, we have learnt to, Create an array using the array() function.
 Create an array using the array() function.
 |-

@@ Line 46: / Line 46: @@
 |-
 |1:21
-|So type ipyhton space hypen pylab
+|So type ipython space hypen pylab
 |-

@@ Line 10: / Line 10: @@
 | 00:06
 | At the end of this tutorial, you will be able to,
 Create arrays using data.
-# Create arrays using data.
+Create arrays from lists.
-# Create arrays from lists.
+Perform basic array operations.
-# Perform basic array operations.
+Create identity matrix.
-# Create identity matrix.
+Use functions zeros(), zeros underscore like(), ones(), ones underscore like().
-# Use functions zeros(), zeros underscore like(), ones(), ones underscore like().
 |-
@@ Line 97: / Line 96: @@
 |-
 |03:33
-|So type ar.reshape within brackets 4 comma 2
+|So type ar.reshape within brackets 4 comma 2 then  ar = ar dot reshape within brackets 2,4
 then  ar = ar dot reshape within brackets 2,4
 |-
@@ Line 322: / Line 320: @@
 |-
 |10:45
-|then a2 = array within brackets square brackets 1 comma 2 comma 3 comma 4
+|then a2 = array within brackets square brackets 1 comma 2 comma 3 comma 4 then type a1 + a2 and hit enter
 then type a1 + a2
 and hit enter
 |-
@@ Line 349: / Line 345: @@
 | 11:41
 |In this tutorial, we have learnt to,
-. Create an array using the array() function.
+Create an array using the array() function.
 |-
 | 11:46
-| 2. Convert a list to an array.
+|Convert a list to an array.
 |-
 | 11:49
-| 3. Perform some basic operations on arrays like addition,multiplication.
+| Perform some basic operations on arrays like addition,multiplication.
 |-
 | 11:53
-| 4. Use functions like - .shape - arrange() - .reshape - zeros() & zeros underscore like() - ones() & ones underscore like()
+| Use functions like - .shape - arrange() - .reshape - zeros() & zeros underscore like() - ones() & ones underscore like()
 |-
@@ Line 369: / Line 365: @@
 |-
 | 12:09
-|1.First one, x = array within brackets square bracket 1 comma 2 comma 3 comma square bracket 5 comma 6 comma 7 is a valid statement
+|First one, x = array within brackets square bracket 1 comma 2 comma 3 comma square bracket 5 comma 6 comma 7 is a valid statement
 |-
@@ Line 377: / Line 373: @@
 |-
 | 12:27
-| 2. What does the  ones underscore like()  function do?
+| What does the  ones underscore like()  function do?
 |-
 | 12:31
-| A. Returns an array of ones with the same shape and type as a given array.
+| Returns an array of ones with the same shape and type as a given array.
 |-
 | 12:37
-|B. Return a new array of given shape and type, filled with ones.
+|Return a new array of given shape and type, filled with ones.
 |-
@@ Line 413: / Line 409: @@
 |-
 | 12:59
-|1. The answer is False.
+| The answer is False.
 |-
@@ Line 425: / Line 421: @@
 |-
 |13:21
-| 1. The function  ones underscores like()  returns an array of ones with the same shape and type as a given array.
+| The function  ones underscores like()  returns an array of ones with the same shape and type as a given array.
 |-

@@ Line 26: / Line 26: @@
 |-
-| 0:39
+| 00:39
 |Unlike lists, arrays cannot have heterogeneous data elements.

@@ Line 316: / Line 316: @@
 |-
 | 10:22
-| Now let us try this a1 = array within brackets square brackets 1 comma 2 comma 3 comma 4
+| Now let us try this a1 = arrays within brackets square brackets 1 comma 2 comma 3 comma 4
 and hit enter
@@ Line 408: / Line 408: @@
 |-
 | 12:56
-| So And the answers,
+| So let's find the answers,
 |-
@@ Line 420: / Line 420: @@
 |-
 |13:10
-|Type  x = array within brackets square brackets 1 comma 2 comma 3 comma square brackets 5 comma 6 comma 7
+|Type  x = array within brackets square brackets 1 comma 2 comma 3 comma within brackets 5 comma 6 comma 7
 |-

@@ Line 42: / Line 42: @@
 |-
 | 1:11
-| Run your IPython interpreter with <tt>space hypen pylab</tt> option, to load the required modules to work with arrays.
+| Run your IPython interpreter with  space hypen pylab option, to load the required modules to work with arrays.
 |-
@@ Line 71: / Line 71: @@
 |-
 | 2:38
-| Now let us use  arange()  function to create the same array as before.
+| Now let us use  arrange()  function to create the same array as before.
 |-
 |2:45
-|For that type ar = arange within bracket 1 comma 9 and hit enter,so type
+|For that type ar = arrange within bracket 1 comma 9 and hit enter,so type
 print ar to get the output.
@@ Line 180: / Line 180: @@
 |-
 | 6:44
-| dtype is nothing but the datatype which is the minimum type required to hold the objects in the sequence.
+| dtype is nothing but the data type which is the minimum type required to hold the objects in the sequence.
 |-

@@ Line 50: / Line 50: @@
 |-
 | 1:28
-| To create an array we will use the function <tt>array()</tt> as,a1 = array within brackets square brackets 1 comma 2 comma 3 comma 4
+| To create an array we will use the function array() as,a1 = array within brackets square brackets 1 comma 2 comma 3 comma 4
 |-
@@ Line 71: / Line 71: @@
 |-
 | 2:38
-| Now let us use <tt>arange()</tt> function to create the same array as before.
+| Now let us use  arange()  function to create the same array as before.
 |-
@@ Line 88: / Line 88: @@
 |-
 | 3:20
-|For this we will have to use the function <tt>reshape()</tt>,
+|For this we will have to use the function reshape() ,
 |-
@@ Line 121: / Line 121: @@
 |-
 |  4:30
-| To find the shape of an array we can use the method <tt>dot shape</tt>,
+| To find the shape of an array we can use the method  dot shape ,
 |-
@@ Line 129: / Line 129: @@
 |-
 | 4:44
-| <tt>a2 dot shape</tt> object is a tuple, and it returned a tuple (2 comma 4).
+|  a2 dot shape  object is a tuple, and it returned a tuple (2 comma 4).
 |-
@@ Line 160: / Line 160: @@
 |-
 |  6:07
-| 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.
+| Well, we would expect an error as it has been previously mentioned that arrays handle elements with the same data type, but it didn't raise an error.
 |-
@@ Line 196: / Line 196: @@
 |-
 | 7:13
-|We can create an identity matrix using the function <tt>identity()</tt>.
+|We can create an identity matrix using the function identity() .
 |-
 | 7:18
-|The function <tt>identity()</tt> takes an integer argument which specifies the size of the desired matrix,
+|The function  identity()   takes an integer argument which specifies the size of the desired matrix,
 |-
@@ Line 212: / Line 212: @@
 |-
 | 7:48
-|<tt>zeros()</tt> 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.
+| 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.
 |-
@@ Line 260: / Line 260: @@
 |-
 | 8:52
-| We see that <tt>a1</tt> is a single dimensional array,
+| We see that  a1  is a single dimensional array,
 |-
@@ Line 348: / Line 348: @@
 | 11:41
 |In this tutorial, we have learnt to,
-. Create an array using the <tt>array()</tt> function.
+. Create an array using the array() function.
 |-
@@ Line 368: / Line 368: @@
 |-
 | 12:09
-|1.First one, <tt><nowiki>x = array within brackets square bracket 1 comma 2 comma 3 comma square bracket 5 comma 6 comma 7</nowiki></tt> is a valid statement
+|1.First one, x = array within brackets square bracket 1 comma 2 comma 3 comma square bracket 5 comma 6 comma 7 is a valid statement
 |-
@@ Line 376: / Line 376: @@
 |-
 | 12:27
-| 2. What does the <tt>ones underscore like()</tt> function do?
+| 2. What does the  ones underscore like()  function do?
 |-
@@ Line 420: / Line 420: @@
 |-
 |13:10
-|Type <nowiki>x = array within brackets square brackets 1 comma 2 comma 3 comma square brackets 5 comma 6 comma 7</nowiki>
+|Type  x = array within brackets square brackets 1 comma 2 comma 3 comma square brackets 5 comma 6 comma 7
 |-
 |13:21
-| 1. The function <tt>ones underscores like()</tt> returns an array of ones with the same shape and type as a given array.
+| 1. The function  ones underscores like()  returns an array of ones with the same shape and type as a given array.
 |-