Sandhya.np14 at 11:57, 11 June 2019

2019-06-11T11:57:02Z

Pratik kamble at 11:16, 11 June 2019

2019-06-11T11:16:19Z

Pratik kamble: Created page with "{|border=1 | Time | Narration |- | 00:01 | Hello friends. Welcome to the tutorial on using '''plot '''command interactively in '''IPython''' |- | 00:08 |At the end of this..."

2019-05-29T13:05:01Z

Created page with "{|border=1 | Time | Narration |- | 00:01 | Hello friends. Welcome to the tutorial on using '''plot '''command interactively in '''IPython''' |- | 00:08 |At the end of this..."

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{|border=1
| Time
| Narration

|-
| 00:01
| Hello friends. Welcome to the tutorial on using '''plot '''command interactively in '''IPython'''

|-
| 00:08
|At the end of this tutorial, you will be able to,

Create simple '''plots''' of '''mathematical''' '''functions'''.

Use the '''Plot''' '''window''' to study '''plots '''better.

|-
| 00:20
| To record this tutorial, I am using

'''Ubuntu Linux 14.04''' operating system

'''Python 3.4.3'''

'''IPython 5.1.0'''

|-
|00:34
|Pre-requisites to practise this tutorial are -

You should know how to run basic '''Python '''commands on the '''ipython console.'''

|-
|00:44
| If not, for relevant '''Python '''tutorials, please visit this website.

|-
| 00:50
| Let us first open the '''Terminal '''by pressing '''Ctrl+Alt+T '''keys simultaneously.

|-
|00:58
|Now, type '''ipython3''' and press '''Enter'''.

|-
| 01:05
| Let us initialise the '''pylab package'''. Type '''percentage''' '''pylab '''and press''' Enter'''

|-
| 01:16
| Let's first understand what is '''Pylab'''

|-
| 01:20
|'''Pylab''' is a convenient '''Python''' '''module''' -

which provides '''plotting''' functionality and has '''mathematical''' and '''scientific''' '''functions'''.

|-
| 01:32
| After running '''percentage pylab '''in the i'''Python console''' you will see a message-

“'''Using matplotlib backend: TkAgg ”.'''

|-
|01:41
| This means '''matplotlib''' is running.

|-
|01:45
| But sometimes you may get an error that says
'''“ImportError: No module named matplotlib”.'''

|-
|01:55
| In such cases, you have to install '''matplotlib''' and run this '''command''' again.

|-
|02:02
| Let's come back to the '''ipython console'''. Type ''''linspace'''' followed by a question mark in '''ipython console. ''' Press '''Enter'''

|-
|02:14
| Please note that the '''command '''is''' linspace '''and''' '''not''' linespace.'''

|-
| 02:20
| The displayed information says that

'''linspace''' returns evenly spaced '''numbers''',
which are calculated over the interval '''start''' and '''stop'''.

|-
|02:34
| Press '''q '''to exit the documentation and return to the '''console.'''

|-
|02:41
| Let's try to generate 100 points from 1 to 100. Type '''linspace brackets 1 comma 100 comma 100'''

|-
|02:58
| Here, 1 is the '''start''' , 100 is the '''stop''' and the next 100 is the number of points. Now, press '''Enter'''.

|-
|03:09
| As you can see, a sequence of numbers from 1 to 100 is displayed.

|-
| 03:15
| Now let's try to generate 200 points between 0 and 1.

|-
|03:21
| We do that by typing '''linspace brackets 0 comma 1 comma 200 '''and press enter.

|-
|03:36
| Here is the expected sequence of numbers.

|-
| 03:40
| In '''linspace,''' the '''start''' and '''stop''' points can be '''integers''', '''decimals''', or '''constants'''.

|-
| 03:48
| Let us now learn about the '''len '''function.

|-
|03:52
| First we will generate 100 points between '''minus pi''' and '''pi'''.

|-
|03:58
| So type '''linspace brackets minus pi comma pi comma 100 '''and''' '''press '''Enter'''.

|-
|04:10
| Here ''''pi'''' is a constant defined by '''pylab'''.

|-
|04:15
| Now, let us save this to a variable, say '''t'''. Press '''Enter'''.

|-
| 04:22
| If we now type '''len bracket t '''and press '''Enter''', we will get the number of points between '''minus''' '''pi''' and '''pi.

|-
|04:32
| '''len''' function gives the no. of elements present in a given sequence.

|-
| 04:37
| Next, let's try and plot a '''cosine''' '''curve''' between '''minus''' '''pi''' and''' pi.'''

|-
|04:43
| For this, we use the '''plot''' command. Type '''plot brackets t comma cos(t) '''and press '''Enter.'''

|-
| 04:59
| As you can see from the '''cosine plot''', '''cos(t)''' gets the '''cosine''' value at every point corresponding to point '''t.'''

|-
| 05:09
| We can also assign the value of '''cos(t) '''to a variable '''cosine''' by typing''' cosine equals to cos(t). '''Press '''Enter'''.

|-
|05:21
| And then '''plot''' by typing '''plot(t comma cosine) '''and press '''Enter'''

|-
| 05:31
| To clear the '''plot''', we have to use the '''clf()''' function. This avoids overlapping of new '''plot'''s over older '''plots'''.

|-
| 05:42
| In the '''console''', type '''clf() '''and press '''Enter. '''The previous '''plot''' is cleared and a blank '''plot window''' is displayed.

|-
| 05:56
| Now, let's try to plot a '''sine''' '''plot'''.

|-
|06:00
| Type '''plot brackets t comma sin(t) '''and press '''Enter.''' A '''sine plot '''is displayed.

|-
| 06:14
| To study the '''plot''' better on the''' plot window,''' we can use various options that are available on it.
Let us have a look at these options.

|-
| 06:25
| Moving the mouse pointer along the '''plot''' gives us the location of each '''point''' on the '''plot.'''

|-
| 06:33
| Notice here. At the bottom left of the window, there are a few buttons.

|-
|06:39
| The right-most among them is for saving the file. Just click on it and type the '''file name'''.

|-
|06:47
| Let us save the '''plot''' by the name '''sin underscore curve''' in '''pdf format'''.

|-
| 06:54
| Click on the dropdown here.As you can see, there are many formats in which to save the '''file.
Formats like '''png, eps, pdf''', and '''ps''' are available.

|-
|07:08
| We have to specify the format that we prefer at the time of saving.

|-
| 07:14
| To the left of the '''save '''button, is the '''slider button.''' Using this '''button''', we can specify the margins of the''' plot window'''.

|-
| 07:24
| To the left of the '''slider button '''is the '''zoom''' '''button'''. It is used to '''zoom''' into the '''plot'''.
Just specify the region to '''zoom''' into.

|-
| 07:37
| The button to the left of '''zoom '''can be used to move the '''axes '''of the '''plot'''.

|-
| 07:41
| The next two buttons with left and right arrow icons, change the state of the '''plot'''.

|-
|07:48
| It takes us to the previous or next state of the '''plot'''. It acts like the back and forward button in a browser.

|-
| 07:57
| The last one is ''''home'''' referring to the initial '''plot. '''

|-
| 08:03
| Pause the video here, try out the following exercise and then resume the video.

|-
|08:09
| Plot '''(sin(x) multiplied by sin(x)) divided by x'''.

1. Save the '''plot''' as '''sinsquarebyx dot pdf'''

2. '''Zoom''' and find the '''maxima'''.

3. Bring it back to initial position.

|-
| 08:26
|This brings us to the end of this tutorial. In this tutorial, we have learnt to,

Start '''IPython''' with '''pylab'''.

Use the '''linspace''' function to create equally spaced points in a region.

|-
|08:42
|Find the length of sequences using '''len''' '''function'''.

Plot mathematical functions using '''plot'''.

Clear drawing area using '''clf'''.

|-
|08:53
| . Usage of buttons in the '''UI''' of the plot window such as -<br/> '''save''', '''zoom,''' '''move''' '''axis''', '''back''' and '''forward '''and '''Home '''

|-
| 09:04
| Here are some self assessment questions for you to solve -

1. Create 100 equally spaced points between '''minus pi by 2''' and '''pi by 2'''

|-
|09:15
| 2. How can we find the length of a sequence ?

|-
|09:19
| 3. What will the command '''linspace(minus pi comma pi comma 100)''' do?

|-
| 09:26
| And the answers,

We use the command '''linspace(minus pi by 2 comma pi by 2 comma 100)''' to create 100 equally spaced lines between the points '''minus pi by 2''' and '''pi by 2'''.

|-
|09:43
|'''len(sequence underscore name) '''is the function used to find out the length of a sequence.

|-
|09:50
| The command '''linspace(minus pi comma pi comma 100)''' will return 100 evenly spaced samples from '''-pi''' to '''pi''' including both '''minus pi '''and '''pi'''.

|-
| 10:06
| The video at the following link summarises the Spoken Tutorial project. If you do not have good bandwidth, you can download and watch it.

|-
| 10:16
| We conduct workshops using Spoken Tutorials and give Certificates. Please contact us.

|-
| 10:24
| Do you have questions in THIS '''Spoken Tutorial?'''

|-
|10:27
| Choose the minute and second where you have the question. Explain your question briefly.
Someone from the '''FOSSEE''' team will answer them. Please visit this site.

|-
| 10:39
| Do you have any general / technical questions? Please visit the forum given in the link.

|-
| 10:46
| The '''FOSSEE '''team coordinates coding of solved examples of popular books.

|-
|10:51
| We give honorarium and certificates for those who do this. For more details, please visit this site.

|-
| 11:00
| The Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India

|-
| 11:07
| This is Usha from IIT Bombay signing off. Thanks for watching.

|}

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Python-3.4.3/C2/Using-plot-command-interactively/English-timed - Revision history

Sandhya.np14 at 11:57, 11 June 2019

Pratik kamble at 11:16, 11 June 2019

Pratik kamble: Created page with "{|border=1 | Time | Narration |- | 00:01 | Hello friends. Welcome to the tutorial on using '''plot '''command interactively in '''IPython''' |- | 00:08 |At the end of this..."