pytutorial/matplotlib/basics

Basics of matplotlib.pyplot

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The goal

Questions to David Rotermund

pylab is a historic interface and its use is strongly discouraged. The equivalent replacement is matplotlib.pyplot

Simple example with plot

import numpy as np
import matplotlib.pyplot as plt  # type: ignore

f: float = 10
t = np.linspace(0, 1.0, 10000)
y = np.sin(t * 2 * np.pi * f)
z = np.cos(t * 2 * np.pi * f)

plt.figure(1)
plt.plot(t, y, label="Sin")
plt.plot(t, z, label="Cos")
plt.xlabel("t")
plt.ylabel("f(t)")
plt.title("Some Functions")
plt.legend()
plt.savefig("Test.pdf")

plt.show()  # This is optinal in Interactive Cell mode

Format Strings

A format string consists of a part for color, marker and line:

fmt = '[marker][line][color]'

Each of them is optional. If not provided, the value from the style cycle is used. Exception: If line is given, but no marker, the data will be a line without markers.

Other combinations such as [color][marker][line] are also supported, but note that their parsing may be ambiguous.

Managing Figure and Axes

axes	Add an Axes to the current figure and make it the current Axes.
cla	Clear the current axes.
clf	Clear the current figure.
close	Close a figure window.
delaxes	Remove an Axes (defaulting to the current axes) from its figure.
fignum_exists	Return whether the figure with the given id exists.
figure	Create a new figure, or activate an existing figure.
gca	Get the current Axes.
gcf	Get the current figure.
get_figlabels	Return a list of existing figure labels.
get_fignums	Return a list of existing figure numbers.
sca	Set the current Axes to ax and the current Figure to the parent of ax.
subplot	Add an Axes to the current figure or retrieve an existing Axes.
subplot2grid	Create a subplot at a specific location inside a regular grid.
subplot_mosaic	Build a layout of Axes based on ASCII art or nested lists.
subplots	Create a figure and a set of subplots.
twinx	Make and return a second axes that shares the x-axis.
twiny	Make and return a second axes that shares the y-axis.

Basic

more Basic

plot	Plot y versus x as lines and/or markers.
errorbar	Plot y versus x as lines and/or markers with attached errorbars.
scatter	A scatter plot of y vs.
step	Make a step plot.
loglog	Make a plot with log scaling on both the x- and y-axis.
semilogx	Make a plot with log scaling on the x-axis.
semilogy	Make a plot with log scaling on the y-axis.
bar	Make a bar plot.
barh	Make a horizontal bar plot.
bar_label	Label a bar plot.
pie	Plot a pie chart.
vlines	Plot vertical lines at each x from ymin to ymax.
hlines	Plot horizontal lines at each y from xmin to xmax.
fill	Plot filled polygons.
polar	Make a polar plot.

Spans

Spans

Spectral

Spectral

Binned

more Binned

hist	Compute and plot a histogram.
hist2d	Make a 2D histogram plot.

Contours

clabel	Label a contour plot.
contour	Plot contour lines.
contourf	Plot filled contours.

2D arrays

more 2D arrays

imshow	Display data as an image, i.e., on a 2D regular raster.

Unstructured triangles

Unstructured triangles

Text and annotations

annotate	Annotate the point xy with text text.
text	Add text to the Axes.
figtext	Add text to figure.
table	Add a table to an Axes.
arrow	Add an arrow to the Axes.
figlegend	Place a legend on the figure.
legend	Place a legend on the Axes.

Vector fields

Vector fields

Axis configuration

autoscale	Autoscale the axis view to the data (toggle).
axis	Convenience method to get or set some axis properties.
box	Turn the axes box on or off on the current axes.
grid	Configure the grid lines.
locator_params	Control behavior of major tick locators.
minorticks_off	Remove minor ticks from the Axes.
minorticks_on	Display minor ticks on the Axes.
rgrids	Get or set the radial gridlines on the current polar plot.
thetagrids	Get or set the theta gridlines on the current polar plot.
tick_params	Change the appearance of ticks, tick labels, and gridlines.
ticklabel_format	Configure the ScalarFormatter used by default for linear Axes.
xlabel	Set the label for the x-axis.
xlim	Get or set the x limits of the current axes.
xscale	Set the xaxis' scale.
xticks	Get or set the current tick locations and labels of the x-axis.
ylabel	Set the label for the y-axis.
ylim	Get or set the y-limits of the current axes.
yscale	Set the yaxis' scale.
yticks	Get or set the current tick locations and labels of the y-axis.
title	Set a title for the Axes.

Layout

more Layout

margins	Set or retrieve autoscaling margins.
subplots_adjust	Adjust the subplot layout parameters.
tight_layout	Adjust the padding between and around subplots.

Colormapping

more Colormapping

clim	Set the color limits of the current image.
colorbar	Add a colorbar to a plot.
sci	Set the current image.
get_cmap	Get a colormap instance, defaulting to rc values if name is None.
set_cmap	Set the default colormap, and applies it to the current image if any.
imread	Read an image from a file into an array.
imsave	Colormap and save an array as an image file.

Configuration

more Configuration

rc	Set the current rcParams. group is the grouping for the rc, e.g., for lines.linewidth the group is lines, for axes.facecolor, the group is axes, and so on. Group may also be a list or tuple of group names, e.g., (xtick, ytick). kwargs is a dictionary attribute name/value pairs, e.g.,::.
rcdefaults	Restore the rcParams from Matplotlib's internal default style.

Output

more Output

draw	Redraw the current figure.
ioff	Disable interactive mode.
ion	Enable interactive mode.
pause	Run the GUI event loop for interval seconds.
savefig	Save the current figure.
show	Display all open figures.

Other

more Other

waitforbuttonpress	Blocking call to interact with the figure.