Python-3.4.3/C2/Saving-plots/English-timed
| Time | Narration |
| 00:01 | Hello friends! Welcome to the tutorial on "Saving Plots". |
| 00:06 | At the end of this tutorial, you will be able to -
save plots using savefig() function, save plots in different formats. |
| 00:15 | To record this tutorial, I am using:
Ubuntu Linux 14.04 operating system, Python 3.4.3, IPython 5.1.0 |
| 00:28 | To practise this tutorial, you should know how to use Plot command interactively.
If not, see the prerequisite Python tutorials on this website. |
| 00:40 | Let us first open the Terminal by pressing Ctrl+Alt+T keys simultaneously.
Now, type ipython3 and press Enter. |
| 00:54 | Let us initialise the 'pylab' package.
Type percentage pylab and press Enter. |
| 01:05 | Let us plot a sine curve from minus 3 pi to 3 pi. |
| 01:10 | First, we will calculate the required points for the plot. |
| 01:14 | To do this, type:
x equals to linspace(minus 3 star pi comma 3 star pi comma 100) in the console. |
| 01:28 | Let us plot a sine curve for the points stored in variable x. |
| 01:33 | Type: plot(x comma sin(x)) in the console and press Enter.
Don't close the plot window for rest of the tutorial. |
| 01:47 | Here you can see we have made a very basic sine plot. Now let us see how to save the plot. |
| 01:54 | For saving the plot, we will use the 'savefig()' function.
Syntax: savefig(fname) savefig function takes one argument which is the filename. |
| 02:05 | Type: savefig('sine.png') and press Enter. |
| 02:12 | This saves the file in present working directory. |
| 02:16 | The characters after the dot in the filename is the extension. It determines the format in which you want to save the file. |
| 02:27 | To check the current working directory, type pwd in the console and press Enter. |
| 02:34 | To save the file in a different directory, type full path of the directory before the filename.
Type: savefig('slash home slash fossee slash sine.png') |
| 02:53 | Note that the above file path is for Linux based file systems. |
| 02:59 | For Windows, give the entire file path as shown here. Here fossee is the username in Windows and sine.png file is to be saved on Desktop. |
| 03:15 | Here we have used an extension dot png. This will ensure that the image is saved as a PNG file. |
| 03:24 | Now let us locate the file sine.png which we had saved earlier. |
| 03:30 | We have saved the file to
(slash)home(slash)fossee. |
| 03:35 | Let us navigate to (slash)home(slash)fossee using the file browser. |
| 03:40 | Open the sine.png file to see the plotted sine curve. |
| 03:46 | savefig can save the plot in many formats such as-
pdf - portable document format, ps - post script, |
| 03:57 | eps - encapsulated post script, to be used with LaTeX documents,
svg - scalable vector graphics, .png - portable network graphics . |
| 04:10 | Pause the video here, try out the following exercise and resume the video. |
| 04:16 | Save the sine plot in the eps format. Let us see the output for this exercise. |
| 04:23 | Type: savefig('slash home slash fossee slash sine.eps') and press Enter. |
| 04:35 | Now let us go to slash home slash fossee and see the new file created. We see the file sine.eps here. |
| 04:48 | Pause the video here, try out the following exercise and resume the video.
Save the sine plot in PDF, PS and SVG formats. |
| 05:00 | This brings us to the end of this tutorial. In this tutorial, we have learnt to:
1. Save plots using the savefig() function. 2. Save the plots in different formats like pdf, ps, png, svg and eps. |
| 05:17 | Here are some assignment questions for you to solve.
1. Which command is used to save a plot? saveplot(), savefig(), savefigure(), saveplt() 2. savefig('sine.png')saves the plot in- the root directory 'slash' (on GNU/Linux, Unix based systems), 'C:' (on windows), |
| 05:40 | will result in an error as full path is not supplied,
the current working directory, predefined directory like “slash documents.” |
| 05:50 | And the answers are-
1. To save a plot, we use the savefig() function. 2. If we save a file without complete path, it gets saved in the current working directory. |
| 06:02 | Please post your timed questions in this forum. |
| 06:07 | Please post your general queries on Python in this forum. |
| 06:12 | FOSSEE team coordinates the TBC project. |
| 06:16 | Spoken Tutorial project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website. |
| 06:25 | This is Prabhu from IIT Bombay, signing off. Thank you. |
