Difference between revisions of "Python/C2/Embellishing-a-plot/English-timed"

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{| border=1
 
{| border=1
−
!Timing
+
|'''Time'''
−
!Narration
+
|'''Narration'''
 +
 
 
|-
 
|-
−
 
+
|  00:00
−
|  0:00
+
|Hello friends. Welcome to the tutorial on '''Embellishing a Plot'''.
−
| Welcome to the tutorial on "Embellishing a Plot".
+
  
 
|-
 
|-
−
| 0:06
+
| 00:06
−
| At the end of this tutorial, you will be able to,
+
| At the end of this tutorial, you will be able to-
−
 
+
Modify the attributes of the plot -- color, line style, line width.
−
# Modify the attributes of the plot -- color, line style,linewidth.
+
Add a title to the plot with embedded '''LaTeX'''.
−
# Add a title to the plot with embedded LaTeX.
+
Label X and Y axes.
−
# Label x and y axes.
+
Add annotations to the plot.
−
# Add annotations to the plot.
+
Set and Get the limits of axes.
−
# Set and Get the limits of axes.
+
−
 
+
−
 
+
  
 
|-
 
|-
−
| 0:27
+
| 00:27
−
| So, Before beginning this tutorial,we would suggest you to complete the tutorial on "Using plot interactively".
+
| So, before beginning this tutorial, we would suggest you to complete the tutorial on '''Using plot interactively'''.
  
 
|-
 
|-
−
| 0:34
+
| 00:34
−
| so,let us start ipython with pylab loaded, open the terminal and type ipython hyphen pylab.
+
| So, let us start '''ipython''' with '''pylab''' loaded. Open the terminal and type: '''ipython hyphen pylab'''.
  
 
|-
 
|-
−
| 0:48
+
| 00:48
−
| We shall first make a simple plot and start decorating it.
+
| We shall first make a simple '''plot''' and start decorating it.
  
 
|-
 
|-
−
| 0:54
+
| 00:54
−
|So type x is equal to linspace within brackets -2,4,20
+
|So, type: '''x is equal to linspace within brackets '''-2, 4, 20'''.
  
 
|-
 
|-
−
| 1:06
+
| 01:06
−
|then type plot(x,sin(x))
+
|Then type plot(x, sin(x)).
  
 
|-
 
|-
−
| 1:15
+
| 01:15
−
| As we can see, the default colour and the default thickness of the line is as decided by pylab.
+
| As we can see, the default colour and the default thickness of the line is as decided by '''pylab'''.
  
 
|-
 
|-
−
| 1:23
+
| 01:23
 
| Wouldn't it be nice if we could control these parameters in the plot?  
 
| Wouldn't it be nice if we could control these parameters in the plot?  
  
 
|-
 
|-
−
| 1:28
+
| 01:28
 
|This is possible by passing additional arguments to the plot command.
 
|This is possible by passing additional arguments to the plot command.
  
 
|-
 
|-
−
| 1:33
+
| 01:33
 
| We shall first clear the figure and plot the same by passing the additional color argument.
 
| We shall first clear the figure and plot the same by passing the additional color argument.
  
 
|-
 
|-
−
| 1:39
+
| 01:39
 
| Pass the argument 'r' for red color.
 
| Pass the argument 'r' for red color.
  
 
|-
 
|-
−
| 1:44
+
| 01:44
−
| So type clf, then plot within brackets x,sin(x),within single quotes r.
+
| So, type '''clf''', then '''plot''' within brackets '''x, sin(x)''', within single quotes r.
  
 
|-
 
|-
−
|  2:13
+
|  02:13
 
| The same plot is seen in red color.
 
| The same plot is seen in red color.
  
 
|-
 
|-
−
| 2:16
+
| 02:16
−
| The thickness of the line can be altered by 'linewidth' argument.
+
| The thickness of the line can be altered by ''''linewidth'''' argument.
  
 
|-
 
|-
−
| 2:20
+
| 02:20
−
|So type plot within brackets x,cos(x),linewidth is equal to 2
+
|So, type: '''plot''' within brackets '''x, cos(x), linewidth is equal to 2'''.
  
 
|-
 
|-
−
| 2:34
+
| 02:34
 
|Now, a plot with line thickness 2 is produced.
 
|Now, a plot with line thickness 2 is produced.
  
 
|-
 
|-
−
| 2:40
+
| 02:40
−
| Pause the video and do this exercise and then resume the video.
+
| Pause the video here and do this exercise and then resume the video.
  
 
|-
 
|-
−
| 2:45
+
| 02:45
 
|Plot sin(x) in blue color along with linewidth as 3.
 
|Plot sin(x) in blue color along with linewidth as 3.
  
 
|-
 
|-
−
| 2:53
+
| 02:53
−
| So, now switch to terminal for solution A combination of color and linewidth would do the job for us.
+
| So, now switch to '''terminal''' for solution. A combination of color and line width would do the job for us.
  
 
|-
 
|-
−
| 3:01
+
| 03:01
−
|So , type clf , then type plot within brackets x, sin(x),within single quotes b,linewidth is equal to 3.
+
|So, type '''clf''' , then type '''plot x, sin(x)''', within single quotes '''b''', '''linewidth is equal to 3'''.
  
 
|-
 
|-
−
| 3:16
+
| 03:16
 
| To get the style of line as bunch of points not joined, pass the linestyle argument with or without color argument.
 
| To get the style of line as bunch of points not joined, pass the linestyle argument with or without color argument.
  
 
|-
 
|-
−
| 3:25
+
| 03:25
−
| So for that type on the terminal clf, then type plot x,sin(x),within single quotes dot.
+
| So, for that, type on the terminal '''clf''', then type: '''plot x, sin(x), dot''' in single quotes.
  
 
|-
 
|-
−
| 3:43
+
| 03:43
 
| We get a plot with only points.
 
| We get a plot with only points.
  
 
|-
 
|-
−
| 3:49
+
| 03:49
−
| To get the same plot in blue color type clf, then type plot within brackets x, sin(x),within single quotes b dot.
+
| To get the same plot in blue color, type: '''clf''', then type '''plot x, sin(x),'''within single quotes '''b dot'''.
  
 
|-
 
|-
−
| 4:02
+
| 04:02
−
| Other available options for passing arguments can be seen in the documentation of plot.
+
| Other available options for passing arguments can be seen in the documentation of '''plot'''.
  
 
|-
 
|-
−
| 4:07
+
| 04:07
−
|For that , you can type in the terminal plot then question mark.
+
|To see that, we can type in the terminal- '''plot''' then question mark.
  
 
|-
 
|-
−
| 4:19
+
| 04:19
 
| So, you can actually go through the documentation.
 
| So, you can actually go through the documentation.
−
 
  
 
|-
 
|-
−
| 4:23
+
| 04:23
−
| So , you pause the video and do this exercise and then resume the video.
+
| So, pause the video here and do this exercise and then resume the video.
  
 
|-
 
|-
−
| 4:28
+
| 04:28
−
|Plot the sine curve with green filled circles.
+
|Plot the '''sine curve''' with green filled circles.
  
 
|-
 
|-
−
| 4:33
+
| 04:33
−
| so ,for solutionNow, switch to terminal . We use a combination of linestyle and color.
+
| So, for solution, now switch to the terminal. We use the combination of '''linestyle''' and color.
  
 
|-
 
|-
−
|4:40
+
|04:40
−
|So ,type clf() then type plot within brackets x,cos(x), within single quotes go.
+
|So, type '''clf()''' then type '''plot''' within brackets '''x, cos(x)''', within single quotes '''go'''.
  
 
|-
 
|-
−
|4:56
+
|04:56
−
|So, Pause the video here, try out the following exercise and resume the video.
+
|So, pause the video here. Try out the following exercise and resume the video.
  
 
|-
 
|-
−
|5:02
+
|05:02
−
|Plot the curve of x versus tan(x) in red dash line and linewidth 3.
+
|Plot the curve of 'x' versus 'tan(x)', in red dash line and linewidth 3.
  
 
|-
 
|-
−
| 5:13
+
| 05:13
−
| So for solution, we will switch to terminal .  
+
| So, for solution, we will switch to terminal.  
  
 
|-
 
|-
−
| 5:18
+
| 05:18
−
|Here we shall use a combination of linewidth argument and linestyle.
+
|Here, we shall use a combination of '''linewidth''' argument and '''linestyle'''.
  
 
|-
 
|-
−
|5:22
+
|05:22
−
|So in terminal you can type clf() then plot within brackets x, cos(x), within single quotes r hyphen hyphen
+
|So, in terminal, you can type '''clf()''' then '''plot''' within brackets '''x, cos(x),''' within single quotes '''r''' hyphen hyphen.
  
 
|-
 
|-
−
| 5:36
+
| 05:36
 
| Now that we know how to produce a bare minimum plot with color, style and thickness of our interest, we shall look at further decorating the plot.
 
| Now that we know how to produce a bare minimum plot with color, style and thickness of our interest, we shall look at further decorating the plot.
  
 
|-
 
|-
−
|  5:46
+
|  05:46
−
| Let us start with a plot for the function minus x squared plus 4x minus 5.
+
| Let us start with a plot for the '''function''' '''minus x squared plus 4x minus 5'''.
  
 
|-
 
|-
−
|5:52
+
|05:52
−
|So for that you have to type clf then plot within brackets x,minus x star x plus 4 star x minus 5,'r',linewidth is equal to 2.
+
|So, for that, you have to type: first '''clf''' then '''plot''' within brackets '''x, minus x star x plus 4 star x minus 5, 'r', linewidth is equal to 2'''.
  
 
|-
 
|-
−
| 6:16
+
| 06:16
 
| As you can see, the figure does not have any description describing the plot.
 
| As you can see, the figure does not have any description describing the plot.
  
 
|-
 
|-
−
| 6:21
+
| 06:21
−
|To add a title to the plot to describe what the plot is,use the <tt>title</tt> command.
+
|To add a '''title''' to the plot to describe what the plot is, use the '''title''' command.
  
 
|-
 
|-
−
|6:26
+
|06:26
−
|So, we can type in the terminal title within brackets and double quotes Parabolic function - x squared plus 4x minus 5
+
|So, we can type in the terminal, '''title''' within brackets and double quotes '''Parabolic function - x squared plus 4x minus 5'''
  
 
|-
 
|-
−
|6:42
+
|06:42
−
|The figure now has a title.
+
|The figure now has a '''title'''.
  
 
|-
 
|-
−
|6:45
+
|06:45
−
| But it is not formatted and does not look clean.
+
| But, it is not formatted and does not look clean.
  
 
|-
 
|-
−
| 6:49
+
| 06:49
−
| It would look shabby if there were fractions and more complex functions like log and exp.
+
| It would look shabby if there were '''fraction'''s and more '''complex function'''s like '''log''' and '''exp'''.
  
 
|-
 
|-
−
| 6:57
+
| 06:57
−
| So, Wouldn't it be good if the title is seen in LaTeX like formatting?
+
| So, Wouldn't it be good if the title is seen in '''LaTeX''' like formatting?
  
 
|-
 
|-
−
| 7:03
+
| 07:03
−
| This is possible by adding a <tt>$</tt> sign before and after the part of the string that should be in LaTeX style.
+
| This is possible by adding a '$' sign before and after the part of the '''string''' that should be in '''LaTeX style'''.
  
 
|-
 
|-
−
|7:10
+
|07:10
−
| So in the command you can type title within brackets and double quotes Parabolic function dollar sign minus x squared plus 4x minus 5 dollar sign
+
| So, in the command you can type: '''title''' within brackets '''Parabolic function dollar sign minus x squared plus 4x minus 5 dollar sign'''.
−
 
+
  
 
|-
 
|-
−
| 7:26
+
| 07:26
 
| As we can see, the polynomial is now formatted.
 
| As we can see, the polynomial is now formatted.
  
 
|-
 
|-
−
| 7:30
+
| 07:30
−
| Pause the video here, try out the following exercise and resume the video.
+
|So, pause the video here. Try out the following exercise and resume the video.
  
 
|-
 
|-
−
| 7:35
+
| 07:35
−
| Change the title of the figure such that the whole title is formatted in LaTeX style.
+
| Change the '''title''' of the figure such that the whole title is formatted in '''LaTeX style'''.
  
 
|-
 
|-
−
| 7:41
+
| 07:41
−
| Switch to terminal for solution.  
+
|So, for that, switch to terminal for solution.  
  
 
|-
 
|-
−
| 7:45
+
| 07:45
−
| The solution is to enclose the whole string in between $.
+
| The solution is to enclose the whole '''string''' in between '$'.
  
 
|-
 
|-
−
|7:51
+
|07:51
−
|So you can type title within brackets dollar sign Parabolic function -x squared plus 4x minus 5 dollar sign.
+
|So, you can type: '''title''' within brackets '''dollar sign Parabolic function -x squared plus 4x minus 5 dollar sign'''.
  
 
|-
 
|-
−
| 8:01
+
| 08:01
−
| Although we have title, the plot is not complete without labelling x and y axes.  
+
| Although we have title, the plot is not complete without labeling x and y axes.  
  
 
|-
 
|-
−
| 8:05
+
| 08:05
 
| we shall label x-axis to "x" and y-axis to "f(x)".
 
| we shall label x-axis to "x" and y-axis to "f(x)".
  
 
|-
 
|-
−
| 8:12
+
| 08:12
−
|So for that you can type in terminal xlabel within brackets in double quotes x , then in terminal ylabel within brackets in double quotes f of x.
+
|So, for that, you can type in terminal: '''xlabel''' within brackets in double quotes '''x ,''' and then '''ylabel''' in terminal within brackets in double quotes '''f of x'''.
  
 
|-
 
|-
−
| 8:31
+
| 08:31
−
| As you can see, <tt>xlabel</tt> and 'ylabel' command takes a string as an argument.  
+
| As you can see, '''xlabel''' and '''ylabel''' commandd take a string as an argument.  
  
 
|-
 
|-
−
| 8:37
+
| 08:37
−
| xlabel sets the label to x-axis as 'x' and ylabel sets the name to the y-axis as 'f(x)'.
+
| '''xlabel''' sets the label to x-axis as 'x' and '''ylabel''' sets the name to the y-axis as 'f(x)'.
−
 
+
  
 
|-
 
|-
−
| 8:50
+
| 08:50
−
| Pause the video here, try out the following exercise and resume the video.
+
|So, now pause the video here, try out the following exercise and resume the video.
  
 
|-
 
|-
−
| 8:57
+
| 08:57
−
| Set the x and y labels as "x" and "f(x)" in LaTeX style.
+
| Set the x and y labels as "x" and "f(x)" in '''LaTeX style'''.
  
 
|-
 
|-
−
| 9:04
+
| 09:04
−
| Since we need LaTeX style formatting, all we have to do is enclose the string in between two $.
+
| Since we need LaTeX style formatting, all we have to do is enclose the '''string''' in between two dollar symbols ($).
  
 
|-
 
|-
−
| 9:10
+
| 09:10
−
| Switch to terminal for solution and type xlabel within brackets dollar sign x dollar sign.
+
| So now, switch to terminal and type: '''xlabel''' within brackets in double quotes in between two dollar signs '''x''' and then type '''ylabel''' and again brackets double quotes in between two dollar signs '''f of x'''.
−
ylabel within brackets and double quotes dollar sign f of x dollar sign.
+
 
   
 
   
−
 
 
|-
 
|-
−
| 9:31
+
| 09:31
 
| The plot is now almost complete except that the points are not named.
 
| The plot is now almost complete except that the points are not named.
  
 
|-
 
|-
−
| 9:37
+
| 09:37
−
| For example the point (2, -1) is the local maxima.
+
| For example, the point (2, -1) is the '''local maxima'''.
  
 
|-
 
|-
−
| 9:42
+
| 09:42
 
| We would like to name the point accordingly.  
 
| We would like to name the point accordingly.  
  
 
|-
 
|-
−
|9:47
+
|09:47
−
|To do this use the function <tt>annotate</tt>.
+
|To do this, use the function '''annotate()'''.
  
 
|-
 
|-
−
|9:49
+
|09:49
−
|So for that you can type in the terminal annotate within brackets in double quotes local maxima comma xy is equal to within brackets 2 comma -1.
+
|So, for that, you can type in the terminal: '''annotate''' within brackets in double quotes '''local maxima comma xy is equal to''' within brackets '''2 comma -1'''.
  
 
|-
 
|-
 
| 10:04
 
| 10:04
−
| As you can see, the first argument to <tt>annotate</tt> command is the name we would like to mark the point as, and the second argument is the co-ordinates of the point at which the name should appear.
+
| As you can see, the first argument to '''annotate''' command is the name we would like to mark the point as. And, the second argument is the co-ordinates of the point at which the name should appear.
  
 
|-
 
|-
 
| 10:18
 
| 10:18
−
| It is a tuple containing two numbers.
+
| It is a '''tuple''' containing two numbers.
  
 
|-
 
|-
Line 310: Line 302:
 
|-
 
|-
 
|10:30
 
|10:30
−
|Make an annotation called "root" at the point (-4, 0).
+
|Make an '''annotation''' called "root", at the point (-4, 0).
  
 
|-
 
|-
 
| 10:38
 
| 10:38
−
| What happens to the first annotation ?
+
| What happens to the first annotation?
  
 
|-
 
|-
 
| 10:43
 
| 10:43
−
| Switch to the terminal for the solution.  
+
| For that, switch to the '''terminal''' for the solution.  
  
 
|-
 
|-
 
|10:46
 
|10:46
−
|As we can see, every annotate command makes a new annotation on the figure.
+
|As we can see, every '''annotate''' command makes a new annotation on the figure.
  
 
|-
 
|-
 
|10:52
 
|10:52
−
|Now we have everything we need to decorate a plot, but the plot would be incomplete if we can not set the limits of axes.  
+
|Now, we have everything we need to decorate a plot but the plot would be incomplete if we can not set the limits of axes.  
  
 
|-
 
|-
Line 334: Line 326:
 
|-
 
|-
 
|11:06
 
|11:06
−
|Else limits also can be get and set from the terminal.
+
|Else, limits also can be get and set from the terminal.
  
 
|-
 
|-
 
| 11:13
 
| 11:13
−
| Use "xlim()" and "ylim()" functions to get the limits.
+
| Use "xlim()" function  and "ylim()" function to get the '''limit'''s.
  
 
|-
 
|-
 
|11:17
 
|11:17
−
|So type in the terminal annotate within brackets in double quotes root comma xy is equal to within brackets minus 4 comma 0.
+
|So, type in the terminal: '''annotate''' within brackets in double quotes '''root''' comma '''xy is equal to''' within brackets '''minus 4 comma 0'''.
  
 
|-
 
|-
 
| 11:32
 
| 11:32
−
| <tt>xlim</tt> function returns the current x axis limits and <tt>ylim</tt> function returns the current y-axis limits.
+
| '''xlim()''' function returns the current x-axis limits and '''ylim()''' function returns the current y-axis limits.
  
 
|-
 
|-
 
|11:41
 
|11:41
−
|Set the limits of x-axis from -4 to 5 by giving command xlim(-4,5).
+
|Set the '''limit'''s of x-axis from -4 to 5 by giving command '''xlim(-4,5)'''. So, in the terminal, you can type: '''xlim()''' and then again '''ylim ()''' then type '''xlim(-4,5)'''.
  
 
|-
 
|-
 
|  12:12
 
|  12:12
−
| Similarly set the limits of y-axis appropriately.
+
| Similarly set the limits of y-axis appropriately. So you can type: '''ylim(-15,2)'''.
  
 
|-
 
|-
Line 362: Line 354:
 
|-
 
|-
 
|12:27
 
|12:27
−
|Set the limits of axes such that the area of interest is the rectangle (-1, -15) and (3, 0)
+
|Set the limits of axes such that the area of interest is the rectangle (-1, -15) and (3, 0).
  
 
|-
 
|-
 
| 12:37
 
| 12:37
−
| Switch to the terminal for the solution.  
+
| Switch to the '''terminal''' for the solution.  
−
 
+
  
 
|-
 
|-
Line 379: Line 370:
 
|-
 
|-
 
|12:51
 
|12:51
−
|So in the command we can type xlim within brackets -1 comma 3 and ylim within brackets -15 comma 0.
+
|So, in the command we can type: '''xlim''' within brackets '''-1 comma 3''' and '''ylim''' within brackets '''-15 comma 0'''.
  
 
|-
 
|-
Line 387: Line 378:
 
|-
 
|-
 
| 13:09
 
| 13:09
−
| This brings us to the end of this tutorial.In this tutorial,we have learnt to,Modify the attributes of plot like color, line width, line style by passing additional arguments.
+
| This brings us to the end of this tutorial. In this tutorial, we have learnt to: Modify the attributes of '''plot''' like '''color, line width, line style''' by passing additional '''argument'''s.
  
 
|-
 
|-
 
| 13:20
 
| 13:20
−
|  Add title to a plot using 'title' command.
+
|  Add '''title''' to a plot using 'title' command.
  
 
|-
 
|-
 
| 13:24
 
| 13:24
−
|  Incorporate LaTeX style formatting by adding a <tt>$</tt> sign before and after the part of the string.
+
|  Incorporate '''LaTeX''' style formatting by adding a '$' sign before and after the part of the '''string'''.
  
 
|-
 
|-
 
| 13:30
 
| 13:30
−
|  Label x and y axes using xlabel() and ylabel() commands.
+
|  '''Label''' x and y axes using '''xlabel()''' function and '''ylabel()''' commands.
  
 
|-
 
|-
 
| 13:36
 
| 13:36
−
| Then, add annotations to a plot using annotate() command.
+
| Then, add annotations to a plot using '''annotate()''' command.
  
 
|-
 
|-
 
| 13:38
 
| 13:38
−
| Get and set the limits of axes using xlim() and ylim() commands.
+
| Get and set the limits of axes using '''xlim()''' and '''ylim()''' commands.
  
 
|-
 
|-
Line 415: Line 406:
 
|-
 
|-
 
| 13:50
 
| 13:50
−
| 1. Draw a plot of cosine graph between -2pi to 2pi with line thickness 4.
+
| 1. Draw a '''plot''' of '''cosine graph''' between '-2pi' to '2pi' with line thickness 4.
  
 
|-
 
|-
 
| 13:57
 
| 13:57
−
| 2. Read through the documentation and find out, is there a way to modify the alignment of text in the command <tt>ylabel</tt>.
+
| 2. Read through the documentation and find out, is there a way to modify the alignment of text in the command '''ylabel'''.
  
 
|-
 
|-
 
| 14:05
 
| 14:05
−
| Yes or No are the options.
+
| '''Yes''' or '''No''' are the options.
  
 
|-
 
|-
 
| 14:07
 
| 14:07
−
| And the final question. How do you set the title as x^2-5x+6 in LaTex style formatting.
+
| And the final question. How do you set the '''title''' as 'x^2-5x+6' in '''LaTex''' style formatting.
−
 
+
  
 
|-
 
|-
 
| 14:15
 
| 14:15
−
| Now, the answers,
+
| Now, the answers:
  
 
|-
 
|-
 
| 14:20
 
| 14:20
−
| 1. In order to plot a cosine graph between the points -2pi and 2pi with line thickness 3,we use the <tt>linspace</tt> and <tt>plot</tt> command as, x = linspace(-2*pi, 2*pi)
+
| 1. In order to plot a '''cosine graph''' between the points '-2pi' and '2pi' with line thickness 4, we use the '''linspace''' and '''plot''' command as- '''x = linspace(-2*pi, 2*pi)'''.
  
 
|-
 
|-
 
| 14:41
 
| 14:41
−
| then plot(x, cos(x), linewidth=4)
+
| then '''plot(x, cos(x), linewidth=4)'''
  
 
|-
 
|-
 
| 14:46
 
| 14:46
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| And the second answer is No. We do not have an option to modify the alignment of text in the command <tt>ylabel</tt>.
+
| And the second answer is '''No'''. We do not have an option to modify the alignment of text in the command '''ylabel'''.
  
 
|-
 
|-
 
|14:53
 
|14:53
−
| Then the third and final one. To set the title in LaTex style formatting,we write the equation between two dollar signs as,
+
| Then the third and final one. To set the title in '''LaTex''' style formatting, we write the equation between two dollar signs as,
−
 
+
'''title("$x^2-5x+6$")'''.
−
title("$x^2-5x+6$")
+
  
 
|-
 
|-
 
| 15:11
 
| 15:11
 
| Hope you have enjoyed this tutorial and found it useful.  
 
| Hope you have enjoyed this tutorial and found it useful.  
−
 
−
 
  
 
|}
 
|}

Latest revision as of 18:00, 20 February 2017

Time Narration
00:00 Hello friends. Welcome to the tutorial on Embellishing a Plot.
00:06 At the end of this tutorial, you will be able to-

Modify the attributes of the plot -- color, line style, line width. Add a title to the plot with embedded LaTeX. Label X and Y axes. Add annotations to the plot. Set and Get the limits of axes.

00:27 So, before beginning this tutorial, we would suggest you to complete the tutorial on Using plot interactively.
00:34 So, let us start ipython with pylab loaded. Open the terminal and type: ipython hyphen pylab.
00:48 We shall first make a simple plot and start decorating it.
00:54 So, type: x is equal to linspace within brackets -2, 4, 20.
01:06 Then type plot(x, sin(x)).
01:15 As we can see, the default colour and the default thickness of the line is as decided by pylab.
01:23 Wouldn't it be nice if we could control these parameters in the plot?
01:28 This is possible by passing additional arguments to the plot command.
01:33 We shall first clear the figure and plot the same by passing the additional color argument.
01:39 Pass the argument 'r' for red color.
01:44 So, type clf, then plot within brackets x, sin(x), within single quotes r.
02:13 The same plot is seen in red color.
02:16 The thickness of the line can be altered by 'linewidth' argument.
02:20 So, type: plot within brackets x, cos(x), linewidth is equal to 2.
02:34 Now, a plot with line thickness 2 is produced.
02:40 Pause the video here and do this exercise and then resume the video.
02:45 Plot sin(x) in blue color along with linewidth as 3.
02:53 So, now switch to terminal for solution. A combination of color and line width would do the job for us.
03:01 So, type clf , then type plot x, sin(x), within single quotes b, linewidth is equal to 3.
03:16 To get the style of line as bunch of points not joined, pass the linestyle argument with or without color argument.
03:25 So, for that, type on the terminal clf, then type: plot x, sin(x), dot in single quotes.
03:43 We get a plot with only points.
03:49 To get the same plot in blue color, type: clf, then type plot x, sin(x),within single quotes b dot.
04:02 Other available options for passing arguments can be seen in the documentation of plot.
04:07 To see that, we can type in the terminal- plot then question mark.
04:19 So, you can actually go through the documentation.
04:23 So, pause the video here and do this exercise and then resume the video.
04:28 Plot the sine curve with green filled circles.
04:33 So, for solution, now switch to the terminal. We use the combination of linestyle and color.
04:40 So, type clf() then type plot within brackets x, cos(x), within single quotes go.
04:56 So, pause the video here. Try out the following exercise and resume the video.
05:02 Plot the curve of 'x' versus 'tan(x)', in red dash line and linewidth 3.
05:13 So, for solution, we will switch to terminal.
05:18 Here, we shall use a combination of linewidth argument and linestyle.
05:22 So, in terminal, you can type clf() then plot within brackets x, cos(x), within single quotes r hyphen hyphen.
05:36 Now that we know how to produce a bare minimum plot with color, style and thickness of our interest, we shall look at further decorating the plot.
05:46 Let us start with a plot for the function minus x squared plus 4x minus 5.
05:52 So, for that, you have to type: first clf then plot within brackets x, minus x star x plus 4 star x minus 5, 'r', linewidth is equal to 2.
06:16 As you can see, the figure does not have any description describing the plot.
06:21 To add a title to the plot to describe what the plot is, use the title command.
06:26 So, we can type in the terminal, title within brackets and double quotes Parabolic function - x squared plus 4x minus 5
06:42 The figure now has a title.
06:45 But, it is not formatted and does not look clean.
06:49 It would look shabby if there were fractions and more complex functions like log and exp.
06:57 So, Wouldn't it be good if the title is seen in LaTeX like formatting?
07:03 This is possible by adding a '$' sign before and after the part of the string that should be in LaTeX style.
07:10 So, in the command you can type: title within brackets Parabolic function dollar sign minus x squared plus 4x minus 5 dollar sign.
07:26 As we can see, the polynomial is now formatted.
07:30 So, pause the video here. Try out the following exercise and resume the video.
07:35 Change the title of the figure such that the whole title is formatted in LaTeX style.
07:41 So, for that, switch to terminal for solution.
07:45 The solution is to enclose the whole string in between '$'.
07:51 So, you can type: title within brackets dollar sign Parabolic function -x squared plus 4x minus 5 dollar sign.
08:01 Although we have title, the plot is not complete without labeling x and y axes.
08:05 we shall label x-axis to "x" and y-axis to "f(x)".
08:12 So, for that, you can type in terminal: xlabel within brackets in double quotes x , and then ylabel in terminal within brackets in double quotes f of x.
08:31 As you can see, xlabel and ylabel commandd take a string as an argument.
08:37 xlabel sets the label to x-axis as 'x' and ylabel sets the name to the y-axis as 'f(x)'.
08:50 So, now pause the video here, try out the following exercise and resume the video.
08:57 Set the x and y labels as "x" and "f(x)" in LaTeX style.
09:04 Since we need LaTeX style formatting, all we have to do is enclose the string in between two dollar symbols ($).
09:10 So now, switch to terminal and type: xlabel within brackets in double quotes in between two dollar signs x and then type ylabel and again brackets double quotes in between two dollar signs f of x.
09:31 The plot is now almost complete except that the points are not named.
09:37 For example, the point (2, -1) is the local maxima.
09:42 We would like to name the point accordingly.
09:47 To do this, use the function annotate().
09:49 So, for that, you can type in the terminal: annotate within brackets in double quotes local maxima comma xy is equal to within brackets 2 comma -1.
10:04 As you can see, the first argument to annotate command is the name we would like to mark the point as. And, the second argument is the co-ordinates of the point at which the name should appear.
10:18 It is a tuple containing two numbers.
10:20 The first is x co-ordinate and second is y co-ordinate.
10:25 Pause the video, do this exercise and then resume the video.
10:30 Make an annotation called "root", at the point (-4, 0).
10:38 What happens to the first annotation?
10:43 For that, switch to the terminal for the solution.
10:46 As we can see, every annotate command makes a new annotation on the figure.
10:52 Now, we have everything we need to decorate a plot but the plot would be incomplete if we can not set the limits of axes.
11:01 This can be done using the button provided on the plot window.
11:06 Else, limits also can be get and set from the terminal.
11:13 Use "xlim()" function and "ylim()" function to get the limits.
11:17 So, type in the terminal: annotate within brackets in double quotes root comma xy is equal to within brackets minus 4 comma 0.
11:32 xlim() function returns the current x-axis limits and ylim() function returns the current y-axis limits.
11:41 Set the limits of x-axis from -4 to 5 by giving command xlim(-4,5). So, in the terminal, you can type: xlim() and then again ylim () then type xlim(-4,5).
12:12 Similarly set the limits of y-axis appropriately. So you can type: ylim(-15,2).
12:22 Pause the video, do this exercise and then resume the video.
12:27 Set the limits of axes such that the area of interest is the rectangle (-1, -15) and (3, 0).
12:37 Switch to the terminal for the solution.
12:40 As we can see, the lower and upper limits of x-axis in the exercise are -1 and 3 respectively.
12:46 The lower and upper limits of y-axis are -15 and 0 respectively.
12:51 So, in the command we can type: xlim within brackets -1 comma 3 and ylim within brackets -15 comma 0.
13:02 This gives us the required rectangle.
13:09 This brings us to the end of this tutorial. In this tutorial, we have learnt to: Modify the attributes of plot like color, line width, line style by passing additional arguments.
13:20 Add title to a plot using 'title' command.
13:24 Incorporate LaTeX style formatting by adding a '$' sign before and after the part of the string.
13:30 Label x and y axes using xlabel() function and ylabel() commands.
13:36 Then, add annotations to a plot using annotate() command.
13:38 Get and set the limits of axes using xlim() and ylim() commands.
13:46 Here are some self assessment questions for you to solve.
13:50 1. Draw a plot of cosine graph between '-2pi' to '2pi' with line thickness 4.
13:57 2. Read through the documentation and find out, is there a way to modify the alignment of text in the command ylabel.
14:05 Yes or No are the options.
14:07 And the final question. How do you set the title as 'x^2-5x+6' in LaTex style formatting.
14:15 Now, the answers:
14:20 1. In order to plot a cosine graph between the points '-2pi' and '2pi' with line thickness 4, we use the linspace and plot command as- x = linspace(-2*pi, 2*pi).
14:41 then plot(x, cos(x), linewidth=4)
14:46 And the second answer is No. We do not have an option to modify the alignment of text in the command ylabel.
14:53 Then the third and final one. To set the title in LaTex style formatting, we write the equation between two dollar signs as,

title("$x^2-5x+6$").

15:11 Hope you have enjoyed this tutorial and found it useful.

Contributors and Content Editors

Gaurav, Kavita salve, Minal, PoojaMoolya, Sandhya.np14, Sneha

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