other:python:jyp_steps
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other:python:jyp_steps [2019/05/29 16:04] jypeter [Matplotlib] Improved |
other:python:jyp_steps [2019/06/03 16:12] jypeter [Useful matplotlib reference pages] Added animations |
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| The matplotlib documentation is good, but not always easy to use. <wrap hi>A good way to start with matplotlib</wrap> is to quickly read the following, practice, and read this section again | The matplotlib documentation is good, but not always easy to use. <wrap hi>A good way to start with matplotlib</wrap> is to quickly read the following, practice, and read this section again | ||
| - Have a quick look at the [[https://matplotlib.org/gallery/index.html|matplotlib gallery]] to get an idea of all you can do with matplotlib. Later, when you need to plot something, go back to the gallery to find some examples that are close to what you need and click on them to view their source code | - Have a quick look at the [[https://matplotlib.org/gallery/index.html|matplotlib gallery]] to get an idea of all you can do with matplotlib. Later, when you need to plot something, go back to the gallery to find some examples that are close to what you need and click on them to view their source code | ||
| + | * some examples are more //pythonic// (ie object oriented) than others, some example mix different styles of coding, all this can be confusing. Try to [[http://matplotlib.org/faq/usage_faq.html#coding-styles|use an object oriented way of doing things]]! | ||
| - Use the free hints provided by JY! | - Use the free hints provided by JY! | ||
| - You will usually **initialize matplotlib** with: ''import matplotlib.pyplot as plt'' | - You will usually **initialize matplotlib** with: ''import matplotlib.pyplot as plt'' | ||
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| * creating a figure and axes with a single line: ''my_page, plot_array = **plt**.subplots(3, 1)'' | * creating a figure and axes with a single line: ''my_page, plot_array = **plt**.subplots(3, 1)'' | ||
| * a Matplotlib **//Artist//** or //Patch// is //something// (e.g a line, a group of markers, text, the legend...) plotted on the Figure/Axis | * a Matplotlib **//Artist//** or //Patch// is //something// (e.g a line, a group of markers, text, the legend...) plotted on the Figure/Axis | ||
| + | * **clearing** the //page// (or part of it): you probably won't need that | ||
| + | * ''my_page.clear()'' or ''my_page.clf()'' or ''plt.clf()'': clear the (current) figure | ||
| + | * ''my_plot.clear()'' or ''my_plot.cla()'': clear the (current) axis | ||
| - some resources for having multiple plots on the same figure | - some resources for having multiple plots on the same figure | ||
| * [[https://matplotlib.org/gallery/recipes/create_subplots.html#sphx-glr-gallery-recipes-create-subplots-py|Easily creating subplots]] | * [[https://matplotlib.org/gallery/recipes/create_subplots.html#sphx-glr-gallery-recipes-create-subplots-py|Easily creating subplots]] | ||
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| * [[https://matplotlib.org/tutorials/intermediate/gridspec.html#sphx-glr-tutorials-intermediate-gridspec-py|Customizing Figure Layouts Using GridSpec and Other Functions]], [[https://matplotlib.org/tutorials/intermediate/constrainedlayout_guide.html|constrained layout]] and [[https://matplotlib.org/tutorials/intermediate/tight_layout_guide.html|tight layout]] | * [[https://matplotlib.org/tutorials/intermediate/gridspec.html#sphx-glr-tutorials-intermediate-gridspec-py|Customizing Figure Layouts Using GridSpec and Other Functions]], [[https://matplotlib.org/tutorials/intermediate/constrainedlayout_guide.html|constrained layout]] and [[https://matplotlib.org/tutorials/intermediate/tight_layout_guide.html|tight layout]] | ||
| - use [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.savefig.html|my_page.savefig(...)]] to save a figure | - use [[https://matplotlib.org/api/_as_gen/matplotlib.pyplot.savefig.html|my_page.savefig(...)]] to save a figure | ||
| + | * <wrap hi>savefig(...) must be called **before** plt.show()!</wrap> | ||
| * ''my_page.savefig('my_plot.pdf')'': save the figure to a pdf file | * ''my_page.savefig('my_plot.pdf')'': save the figure to a pdf file | ||
| * ''my_page.savefig('my_plot.png', dpi=200, transparent=True, bbox_inches='tight')'': save the figure to a png file at a higher resolution than the default (default is 100 dots per inch), with a transparent background and no extra space around the figure | * ''my_page.savefig('my_plot.png', dpi=200, transparent=True, bbox_inches='tight')'': save the figure to a png file at a higher resolution than the default (default is 100 dots per inch), with a transparent background and no extra space around the figure | ||
| - | * display the figure and its plots, and start interacting (zooming, ...) with them:\\ ''plt.show()'' | + | - **display** the figure and its plots, and **start interacting** (zooming, panning...) with them:\\ ''plt.show()'' |
| - | - some examples are more //pythonic// (ie object oriented) than others, some example mix different styles of coding, all this can be confusing. Try to [[http://matplotlib.org/faq/usage_faq.html#coding-styles|use an object oriented way of doing things]]! | + | - it may be hard to (remember how to) **work with colors**. Some examples from the [[https://matplotlib.org/gallery/index.html]] can help you! |
| - | - it may be hard to (remember how to) work with colors. Some examples from the [[https://matplotlib.org/gallery/index.html]] can help you! | + | |
| * [[https://matplotlib.org/examples/pylab_examples/leftventricle_bulleye.html|leftventricle_bulleye.py]]: associating different types of colormaps to a plot and colorbar | * [[https://matplotlib.org/examples/pylab_examples/leftventricle_bulleye.html|leftventricle_bulleye.py]]: associating different types of colormaps to a plot and colorbar | ||
| * [[https://matplotlib.org/examples/api/colorbar_only.html|colorbar_only.py]]: the different types of colorbars (or plotting only a colorbar) | * [[https://matplotlib.org/examples/api/colorbar_only.html|colorbar_only.py]]: the different types of colorbars (or plotting only a colorbar) | ||
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| * [[https://matplotlib.org/examples/color/named_colors.html|named_colors.py]]: named colors | * [[https://matplotlib.org/examples/color/named_colors.html|named_colors.py]]: named colors | ||
| * More details about the colors below, in the [[#graphics_related_resources|Resources section]] | * More details about the colors below, in the [[#graphics_related_resources|Resources section]] | ||
| - | - sometimes the results of the python/matplolib commands are displayed immediately, sometimes not. It depends if you are in [[http://matplotlib.org/faq/usage_faq.html#what-is-interactive-mode|interactive or non-interactive]] mode | ||
| - | - if your matplotlib is executed in a batch script, it will generate an error when trying to create (''show()'') a plot, because matplotlib expects to be able to display the figure on a screen by default. | ||
| - | * Check how you can [[https://matplotlib.org/faq/howto_faq.html?highlight=web#generate-images-without-having-a-window-appear|generate images offline]] | ||
| - | - the documentation may mention [[http://matplotlib.org/faq/usage_faq.html#what-is-a-backend|backends]]. What?? Basically, you use python commands to create a plot, and the backend is the //thing// that will render your plot on the screen or in a file (png, pdf, etc...) | ||
| - if you don't see a part of what you have plotted, maybe it's hidden behind other elements! Use the [[https://matplotlib.org/examples/pylab_examples/zorder_demo.html|zorder parameter]] to explicitly specify the plotting order/layers | - if you don't see a part of what you have plotted, maybe it's hidden behind other elements! Use the [[https://matplotlib.org/examples/pylab_examples/zorder_demo.html|zorder parameter]] to explicitly specify the plotting order/layers | ||
| * things should automatically work //as expected// if //zorder// is not explicitly specified | * things should automatically work //as expected// if //zorder// is not explicitly specified | ||
| * Use the ''zorder=NN'' parameter when creating objects. ''NN'' is an integer where 0 is the lowest value (the farthest from the eye), and objects are plotted above objects with a lower //zorder// value | * Use the ''zorder=NN'' parameter when creating objects. ''NN'' is an integer where 0 is the lowest value (the farthest from the eye), and objects are plotted above objects with a lower //zorder// value | ||
| * Use ''matplotlib_object.set_order(NN)'' to change the order after an object has been created | * Use ''matplotlib_object.set_order(NN)'' to change the order after an object has been created | ||
| - | - Read the [[http://www.labri.fr/perso/nrougier/teaching/matplotlib/|Matplotlib tutorial by Nicolas Rougier]] | + | - sometimes the results of the python/matplolib commands are displayed immediately, sometimes not. It depends if you are in [[http://matplotlib.org/faq/usage_faq.html#what-is-interactive-mode|interactive or non-interactive]] mode |
| + | - if your matplotlib is executed in a batch script, it will generate an error when trying to create (''show()'') a plot, because matplotlib expects to be able to display the figure on a screen by default. | ||
| + | * Check how you can [[https://matplotlib.org/faq/howto_faq.html?highlight=web#generate-images-without-having-a-window-appear|generate images offline]] | ||
| + | - the documentation may mention [[http://matplotlib.org/faq/usage_faq.html#what-is-a-backend|backends]]. What?? Basically, you use python commands to create a plot, and the backend is the //thing// that will render your plot on the screen or in a file (png, pdf, etc...) | ||
| + | - Read the [[https://github.com/rougier/matplotlib-tutorial|Matplotlib tutorial by Nicolas Rougier]] | ||
| - Download the [[http://matplotlib.org/contents.html|pdf version of the manual]]. **Do not print** the 2300+ pages of the manual! Read the beginner's guide (Chapter //FIVE// of //Part II//) and have a super quick look at the table of contents of the whole document. | - Download the [[http://matplotlib.org/contents.html|pdf version of the manual]]. **Do not print** the 2300+ pages of the manual! Read the beginner's guide (Chapter //FIVE// of //Part II//) and have a super quick look at the table of contents of the whole document. | ||
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| * example: the default figure size (inches) is ''mpl.rcParams['figure.figsize']'' (''[6.4, 4.8]'') | * example: the default figure size (inches) is ''mpl.rcParams['figure.figsize']'' (''[6.4, 4.8]'') | ||
| * current settings' file: ''mpl.matplotlib_fname()'' | * current settings' file: ''mpl.matplotlib_fname()'' | ||
| + | * [[https://matplotlib.org/api/animation_api.html|Animations]] ([[https://matplotlib.org/gallery/index.html#animation|demo]]) | ||
| ==== Misc Matplotlib tricks ==== | ==== Misc Matplotlib tricks ==== | ||
other/python/jyp_steps.txt · Last modified: 2024/03/07 10:15 by jypeter
