Difference between revisions of "Matplotlib"
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[[Category:Python]] | [[Category:Python]] | ||
Using the [https://matplotlib.org/tutorials/introductory/pyplot.html#sphx-glr-tutorials-introductory-pyplot-py pyplot] functions only until now. | Using the [https://matplotlib.org/tutorials/introductory/pyplot.html#sphx-glr-tutorials-introductory-pyplot-py pyplot] functions only until now. | ||
+ | |||
;import matplotlib.pyplot as plt | ;import matplotlib.pyplot as plt | ||
:Get the pyplot library. We assume this is done in all examples on this page. | :Get the pyplot library. We assume this is done in all examples on this page. | ||
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;plt.legend() | ;plt.legend() | ||
:Add a legend to the plot. Default legend is the label, specify an alternative legend text as list. | :Add a legend to the plot. Default legend is the label, specify an alternative legend text as list. | ||
+ | ;plt.ylim(min,max) | ||
+ | :Fix the y-axis (xlim for the x-axis) | ||
;plt.show() | ;plt.show() | ||
:Show the current figure. | :Show the current figure. |
Revision as of 23:11, 20 February 2021
Using the pyplot functions only until now.
- import matplotlib.pyplot as plt
- Get the pyplot library. We assume this is done in all examples on this page.
- plt.figure(2)
- Initialize a new figure. figure(1) is initialized by default.
- plt.subplot(211)
- Create 1st subplot in figure(1) (212 is the 2nd subplot in figure(1). Return an 'AxesSubplot' object.
- 211 : Split the figure in 2, figure(1) subplot 1
- The subplot can be specified as 2,1,1 too which comes in handy when you have to generate subplots on the fly.
- fig,ax = plt.subplots()
- Return Figure and AxeSubPlot object. Same as:
fig = plt.figure()
ax = fig.add_subplot(111)
- plt.plot(array)
- Create the graphical object from the values in the array. Show the graph if your environment (e.g. jupyter) supports it.
- When you do more plots without changing figure or subplot the result will be added to the current figure.
- plt.legend()
- Add a legend to the plot. Default legend is the label, specify an alternative legend text as list.
- plt.ylim(min,max)
- Fix the y-axis (xlim for the x-axis)
- plt.show()
- Show the current figure.
- plt.savefig('plot.png')
- Save the plot on file
Show the image:
firefox plot.png
eog plot.png
shotwell plot.png
Selfexplaning example code:
plt.plot(array)
plt.title('Set the graph title')
plt.suptitle('Set the graph super title')
plt.xlabel('Set the x label')
plt.ylabel('Set the y label')
plt.show()
With subplots, more lines and legends
ax = plt.subplot(111)
lineA = ax.plot(array,label='Alabel')
lineB = ax.plot(array,label='Blabel')
ax.legend()
Formatting
- plt.plot(x,y,format)
- Draw lines
- plt.bar(x,y,format)
- Draw bars
- plt.scatter(x,y,format)
- Draw points
The 'x' and 'format' arguments are optional. 'x' and 'y' are lists that specify respectively the X-axis and the Y-axis. When only a labeled list like numpy arrays or pandas Series is provided the index makes the X, the values the Y.
The next argument defines the format as <colorchar><format>
Format | Meaning |
---|---|
b- | Blue Solid line, the default |
r-- | Red Dashed line |
b: | Blue Dotted line |
r. | Red Dots |
g-. | Green dashes and dots |
gb | Green Squares |
y^ | Yellow Triangles |
yo | Yellow Balls |