Difference between revisions of "Python/C2/Using-the-plot-command-interactively/English-timed"
From Script | Spoken-Tutorial
Sandhya.np14 (Talk | contribs) |
Sandhya.np14 (Talk | contribs) |
||
Line 71: | Line 71: | ||
|- | |- | ||
|01:57 | |01:57 | ||
− | |we do that by typing''' linspace''' within brackets ''0 comma 1 comma 200''. | + | |we do that by typing''' linspace''' within brackets '''0 comma 1 comma 200'''. |
|- | |- | ||
| 02:11 | | 02:11 | ||
− | | Here, | + | | Here, 0 is the start, 1- the stop and 200- the number of points. |
|- | |- | ||
| 02:18 | | 02:18 | ||
− | | In linspace the start and stop points can be integers, decimals | + | | In '''linspace''', the start and stop points can be integers, decimals or constants. |
|- | |- | ||
| 02:24 | | 02:24 | ||
− | |Let's try and get | + | |Let's try and get 100 points between minus 'pi' to 'pi'. |
|- | |- | ||
| 02:30 | | 02:30 | ||
− | | Here 'pi' is a constant defined by ''pylab''. | + | | Here 'pi' is a constant defined by '''pylab'''. |
|- | |- | ||
| 02:34 | | 02:34 | ||
− | | Save this to the variable,say | + | | Save this to the variable, say 'p'. |
|- | |- | ||
| 02:52 | | 02:52 | ||
− | | If we now type | + | | If we now type 'len' within brackets 'p', we will get the no. of points. |
|- | |- | ||
| 03:05 | | 03:05 | ||
− | | ''len'' function gives the no of | + | | '''len''' function gives the no. of '''element'''s of a sequence. |
|- | |- | ||
| 03:11 | | 03:11 | ||
− | | Let's try and plot a cosine curve between minus pi and pi. For this we use the plot command. Here ''cos(p)'' gets the cosine value at every point corresponding to point p. | + | | Let's try and plot a '''cosine curve''' between minus 'pi' and 'pi'. For this, we use the '''plot''' command. Here, '''cos(p)''' gets the 'cosine' value at every point corresponding to point 'p'. |
|- | |- | ||
| 03:50 | | 03:50 | ||
− | | We can save ''cos(p)'' to variable cosine and then plot it using the plot function. | + | | We can save '''cos(p)''' to variable 'cosine' and then plot it using the '''plot''' function. |
|- | |- | ||
| 03:57 | | 03:57 | ||
− | | Now to clear the plot ,we use the ''clf'' closing brackets function | + | | Now, to clear the plot, we use the '''clf''' closing brackets function. |
|- | |- | ||
| 04:19 | | 04:19 | ||
− | | This is done | + | | This is done because, if we wish to make another plot, it will overlap the previous plot. |
|- | |- | ||
| 04:25 | | 04:25 | ||
− | | As we do not wish to clutter the area with overlaid plots , we just clear it with ''clf()''. | + | | As we do not wish to clutter the area with overlaid plots, we just clear it with '''clf()'''. |
|- | |- | ||
|04:34 | |04:34 | ||
− | |Now, | + | |Now, let's try a 'sine plot'. |
|- | |- | ||
| 05:04 | | 05:04 | ||
− | | We can study the plot better on the plot window by using the various options available on it. | + | | We can study the plot better on the '''plot window''' by using the various options available on it. |
|- | |- | ||
Line 135: | Line 135: | ||
|- | |- | ||
| 05:14 | | 05:14 | ||
− | | As we can observe, moving the mouse pointer along the plot gives us the location of each point on the plot | + | | As we can observe, moving the '''mouse pointer''' along the plot gives us the location of each point on the plot. |
|- | |- | ||
| 05:26 | | 05:26 | ||
− | | To the bottom left of the window,there are a few buttons. | + | | To the bottom left of the window, there are a few buttons. |
|- | |- | ||
Line 151: | Line 151: | ||
|- | |- | ||
| 05:48 | | 05:48 | ||
− | |We will save the file by the name | + | |We will '''save''' the file by the name 'sin_curve' in ''''pdf' format'''. |
|- | |- | ||
| 06:00 | | 06:00 | ||
− | | As you can see we can specify the format of file from the '' | + | | As you can see, we can specify the format of file from the '''drop-down'''. |
|- | |- | ||
| 06:05 | | 06:05 | ||
− | |Formats like'' png ,eps ,pdf, ps'' are available. | + | |Formats like''' png, eps, pdf, ps''' are available. |
|- | |- | ||
| 06:17 | | 06:17 | ||
− | | Left to the save button is the slider button by which we can specify the margins. | + | | Left to the '''save''' button is the '''slider''' button by which we can specify the margins. |
|- | |- | ||
| 06:25 | | 06:25 | ||
− | | Left to this is the zoom button by which we can zoom into the plot. | + | | Left to this is the '''zoom''' button by which we can zoom into the plot. |
|- | |- | ||
Line 187: | Line 187: | ||
|- | |- | ||
| 07:06 | | 07:06 | ||
− | | The last one is 'home' referring to the initial plot. | + | | The last one is '''home''', referring to the initial plot. |
|- | |- | ||
Line 195: | Line 195: | ||
|- | |- | ||
| 07:20 | | 07:20 | ||
− | |Plot ''(sin(x) into sin(x))'' by x. | + | |Plot '''(sin(x) into sin(x))''' by x. |
|- | |- | ||
| 07:26 | | 07:26 | ||
− | | 1. Save the plot by the sin square by ''x.pdf ''in pdf format. | + | | 1. '''Save''' the plot by the sin square by ''x.pdf ''in pdf format. |
|- | |- | ||
| 07:33 | | 07:33 | ||
− | | Second one. ''Zoom'' and find the'' maxima''. | + | | Second one. ''Zoom'' and find the '''maxima'''. |
|- | |- | ||
Line 211: | Line 211: | ||
|- | |- | ||
| 07:44 | | 07:44 | ||
− | | Now, | + | | Now, let's revise quickly what we have learnt today- |
|- | |- | ||
| 07:49 | | 07:49 | ||
− | |To Study ''Ipython'' with ''pylab''. | + | |* To Study '''Ipython''' with '''pylab'''. |
|- | |- | ||
| 07:52 | | 07:52 | ||
− | | To Use the ''linspace ''function to create ''num'' equally spaced points in a region. | + | |* To Use the '''linspace '''function to create '''num''' equally spaced points in a region. |
|- | |- | ||
| 07:57 | | 07:57 | ||
− | |To Find the length of sequences using ''len'' function. | + | |* To Find the length of sequences using '''len''' function. |
|- | |- | ||
| 08:01 | | 08:01 | ||
− | | | + | |* Plot mathematical functions using '''plot'''. |
|- | |- | ||
| 08:05 | | 08:05 | ||
− | | To clear drawing area using ''clf''. | + | |* To clear drawing area using '''clf'''. |
|- | |- | ||
| 08:08 | | 08:08 | ||
− | | To Use the'' UI'' of plot for studying it better and using functionality like save,zoom and moving the plots on ''x and y axis''. | + | |* To Use the'' UI'' of plot for studying it better and using functionality like '''save, zoom''' and moving the plots on ''x and y axis''. |
|- | |- | ||
| 08:23 | | 08:23 | ||
− | | Create 100 equally spaced points between minus pi by | + | | Create 100 equally spaced points between minus pi by 2 and pi by 2? |
|- | |- | ||
| 08:31 | | 08:31 | ||
− | |Second one is | + | |Second one is- How do you clear a figure in''' ipython'''? |
|- | |- | ||
| 08:36 | | 08:36 | ||
− | |The third one | + | |The third one- How do you find the length of a sequence? |
|- | |- | ||
| 08:43 | | 08:43 | ||
− | | And the answers are | + | | And the answers are- |
|- | |- | ||
| 08:45 | | 08:45 | ||
− | |1.We use the command ''linspace within brackets minus pi by | + | |1. We use the command '''linspace''' within brackets '''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''. |
|- | |- | ||
| 09:03 | | 09:03 | ||
− | |Second one | + | |Second one- We use''' clf '''closing bracket function to clear a figure. |
|- | |- | ||
| 09:11 | | 09:11 | ||
− | |Third one | + | |Third one- '''len''' within brackets 'sequence_name' is the function used to find out the length of a sequence. |
|- | |- |
Revision as of 22:25, 23 September 2015
Time | Narration |
00:00 | Hello friends and welcome to the tutorial on creating simple plots using iPython. |
00:06 | I hope you have iPython running on your computer. |
00:10 | At the end of this tutorial, you will be able to:
|
00:20 | Let's start ipython. |
00:22 | Open the terminal and type: ipython -pylab and hit Enter. |
00:35 | Pylab is a python library which provides plotting functionality. |
00:39 | It provides many other important mathematical and scientific functions. |
00:43 | After running IPython -pylab in the shell, you will see some information about 'ipython' and pylab followed by the In[1] prompt. |
00:55 | But, if you get an error like 'ERROR: matplotlib could NOT be imported! Starting normal IPython.' |
01:02 | then you will have to install the matplotlib and run this command again. |
01:08 | Now type: 'linspace' followed by a '?' mark in your ipython shell. |
01:19 | As the documentation says, it "returns 'num' evenly spaced samples, calculated over the interval 'start' and 'stop'". |
01:29 | To illustrate this, let's try to generate 100 points. |
01:33 | Type: linspace within brackets 1 comma 100 comma 100 and hit Enter. |
01:47 | As you can see, a sequence of numbers from 1 to 100 appears. |
01:52 | Now let's try to generate 200 points between 0 and 1. |
01:57 | we do that by typing linspace within brackets 0 comma 1 comma 200. |
02:11 | Here, 0 is the start, 1- the stop and 200- the number of points. |
02:18 | In linspace, the start and stop points can be integers, decimals or constants. |
02:24 | Let's try and get 100 points between minus 'pi' to 'pi'. |
02:30 | Here 'pi' is a constant defined by pylab. |
02:34 | Save this to the variable, say 'p'. |
02:52 | If we now type 'len' within brackets 'p', we will get the no. of points. |
03:05 | len function gives the no. of elements of a sequence. |
03:11 | Let's try and plot a cosine curve between minus 'pi' and 'pi'. For this, we use the plot command. Here, cos(p) gets the 'cosine' value at every point corresponding to point 'p'. |
03:50 | We can save cos(p) to variable 'cosine' and then plot it using the plot function. |
03:57 | Now, to clear the plot, we use the clf closing brackets function. |
04:19 | This is done because, if we wish to make another plot, it will overlap the previous plot. |
04:25 | As we do not wish to clutter the area with overlaid plots, we just clear it with clf(). |
04:34 | Now, let's try a 'sine plot'. |
05:04 | We can study the plot better on the plot window by using the various options available on it. |
05:11 | Let us have a look at these options. |
05:14 | As we can observe, moving the mouse pointer along the plot gives us the location of each point on the plot. |
05:26 | To the bottom left of the window, there are a few buttons. |
05:30 | The right most among them is for saving the file. |
05:35 | Just click on it and type the file name. |
05:48 | We will save the file by the name 'sin_curve' in 'pdf' format. |
06:00 | As you can see, we can specify the format of file from the drop-down. |
06:05 | Formats like png, eps, pdf, ps are available. |
06:17 | Left to the save button is the slider button by which we can specify the margins. |
06:25 | Left to this is the zoom button by which we can zoom into the plot. |
06:30 | Just specify the region to zoom into. |
06:40 | The button to the left of it can be used to move the axes of the plot. |
06:50 | The next two buttons with left and right arrow icons change the state of the plot and take it to the previous state it was in. |
07:00 | It more or less acts like the back and forward button in a browser. |
07:06 | The last one is home, referring to the initial plot. |
07:13 | Pause the video here, try out the following exercise and resume the video. |
07:20 | Plot (sin(x) into sin(x)) by x. |
07:26 | 1. Save the plot by the sin square by x.pdf in pdf format. |
07:33 | Second one. Zoom and find the maxima. |
07:37 | 3. Bring it back to initial position. |
07:44 | Now, let's revise quickly what we have learnt today- |
07:49 | * To Study Ipython with pylab. |
07:52 | * To Use the linspace function to create num equally spaced points in a region. |
07:57 | * To Find the length of sequences using len function. |
08:01 | * Plot mathematical functions using plot. |
08:05 | * To clear drawing area using clf. |
08:08 | * To Use the UI of plot for studying it better and using functionality like save, zoom and moving the plots on x and y axis. |
08:23 | Create 100 equally spaced points between minus pi by 2 and pi by 2? |
08:31 | Second one is- How do you clear a figure in ipython? |
08:36 | The third one- How do you find the length of a sequence? |
08:43 | And the answers are- |
08:45 | 1. We use the command linspace within brackets 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. |
09:03 | Second one- We use clf closing bracket function to clear a figure. |
09:11 | Third one- len within brackets 'sequence_name' is the function used to find out the length of a sequence. |
09:20 | Hope you have enjoyed and found it useful. |
09:24 | Thank you! |