[PYTHON] Matplotlib Basics / Differences between fig and axes

Overview Since the figure and add_subplot of matplotlib are magical in me, I will summarize them in an article to deepen my understanding.

The following import is assumed.

import matplotlib.pyplot as plt

Figure In matplotlib, the following magic is often described at the beginning.

fig = plt.figure()

figure () creates a Figure instance that reserves the entire drawing area. Image of preparing a large canvas or whiteboard.


It can be used without arguments, but the following arguments can be specified.

argument processing
figsize Specify drawing size in tuple format
The unit is inches
dpi Specify the number of dots per inch
facecolor Specify background color
edgecolor Specify the border color
The default border width is 0.0, so linewidth is required
linewidth Specify the border width

Axes(add_subplot) I often see the following magic at the beginning.

fig = plt.figure()
ax = fig.add_subplot(1,1,1)

ʻAdd_subplot` creates a graph drawing area on the entire drawing area Figure. An image of pasting paper on a whiteboard and drawing a graph on the paper. The instance created at this time is a little complicated with the ** Axes ** class.

The relationship image between Figure and Axes (subplot) is as follows.



The argument of add_subplot is specified for the following purposes.

argument processing
The first one Specify the number of lines
Second Specify the number of columns
Third Specify the drawing location

Divide the previously generated figure by the number of matrices specified in the first and second, and draw the graph in the place specified in the third.

For example, ʻadd_subplot (3,3,5) specifies the middle cell of the Figure divided by 3x3. image.png

By the way, ʻadd_subplot (1,1,1) is synonymous with ʻadd_subplot (111).

Try to describe

Once you understand this, all you have to do is draw the graph on the Axes generated by ʻadd_subplot`.

fig = plt.figure()
ax = fig.add_subplot(111)

ax.hist([1, 2, 3])

It looks like this when drawing a rough graph with a stop of thinking. image.png

Reference I refer to this article. Basics of matplotlib drawing-for those who don't understand figs and axes

Recommended Posts

Matplotlib Basics / Differences between fig and axes
Summary of Differences Between Ruby on Rails and Django ~ Basics ~
Differences between yum commands and APT commands
[Note] Conflict between matplotlib and zstd
Differences between symbolic links and hard links
Differences between Python, stftime and strptime
Japanese settings for matplotlib and Seaborn axes
Differences in authenticity between Python and JavaScript
Differences between Ruby and Python in scope
Differences in syntax between Python and Java
Differences between Numpy 1D array [x] and 2D array [x, 1]
Differences in multithreading between Python and Jython
Differences between Django's request.POST ['hoge'] and request.POST.get ('hoge')
Differences between Ruby and Python (basic syntax)
Differences between queryStringParameters and multiValueQueryStringParameters in AWS Lambda
Summary of the differences between PHP and Python
Draw multiple graphs using matplotlib figures and axes
#Python basics (#matplotlib)
Differences and commonalities between dict, list, and tuple types
Differences between glibc, musl libc and go resolvers
Differences between numpy and pandas methods for finding variance
Between parametric and nonparametric
Perceptron basics and implementation
matplotlib this and that
Adjust axes with matplotlib
I tried to enumerate the differences between java and python