How do I draw a grid onto a plot in Python?

Question

I just finished writing code to make a plot using pylab in Python and now I would like to superimpose a grid of 10x10 onto the scatter plot. How do I do that?

My current code is the following:

x = numpy.arange(0, 1, 0.05)
y = numpy.power(x, 2)

fig = plt.figure()
ax = fig.gca()
ax.set_xticks(numpy.arange(0, 1, 0.1))
ax.set_yticks(numpy.arange(0, 1., 0.1))
plt.scatter(x, y)
plt.show()

And its output is:

What I would like is the following output:

EDIT: Added an exemple, based on Andrey Sobolev's answer

score 275 · Answer 1 · edited Mar 20 '17 at 17:42

275

You want to use pyplot.grid:

x = numpy.arange(0, 1, 0.05)
y = numpy.power(x, 2)

fig = plt.figure()
ax = fig.gca()
ax.set_xticks(numpy.arange(0, 1, 0.1))
ax.set_yticks(numpy.arange(0, 1., 0.1))
plt.scatter(x, y)
plt.grid()
plt.show()

ax.xaxis.grid and ax.yaxis.grid can control grid lines properties.

Enter image description here

edited Mar 20 '17 at 17:42

Peter Mortensen

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answered Nov 21 '11 at 11:00

Andrey Sobolev

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2

Any idea why this is producing a plot with no grid for me? – endolith Feb 26 '15 at 15:45
Oh I think it's a `matplotlibrc` issue, I had grid style defined as solid lines and that doesn't work anymore? – endolith Feb 26 '15 at 15:51
1

Actually it should work. At least, it works for me - setting `mpl.rcParams['grid.linestyle'] = "-"` does produce a plot with solid grid lines. What is your `grid.linestyle`? – Andrey Sobolev Feb 27 '15 at 07:53
It was `-`. I don't know why it stopped working. I'll investigate someday. – endolith Feb 28 '15 at 00:51
5

Alternatively it might better to do `ax.scatter(x,y)` and `ax.grid(True)`. – foghorn Apr 02 '15 at 22:04
@endolith, not sure if this helps, but it wasn't working for me because I was calling plt.grid, instead of plt.grid() – Bernardo Jan 21 '22 at 08:18

score 80 · Answer 2 · edited Jan 08 '18 at 19:09

To show a grid line on every tick, add

plt.grid(True)

For example:

import matplotlib.pyplot as plt

points = [
    (0, 10),
    (10, 20),
    (20, 40),
    (60, 100),
]

x = list(map(lambda x: x[0], points))
y = list(map(lambda x: x[1], points))

plt.scatter(x, y)
plt.grid(True)

plt.show()

In addition, you might want to customize the styling (e.g. solid line instead of dashed line), add:

plt.rc('grid', linestyle="-", color='black')

For example:

import matplotlib.pyplot as plt

points = [
    (0, 10),
    (10, 20),
    (20, 40),
    (60, 100),
]

x = list(map(lambda x: x[0], points))
y = list(map(lambda x: x[1], points))

plt.rc('grid', linestyle="-", color='black')
plt.scatter(x, y)
plt.grid(True)

plt.show()

Its possible to show the grid, although the axes is not shown? — Nikolai Ehrhardt, Apr 09 '22 at 11:47

score 35 · Answer 3 · edited Jul 04 '19 at 22:41

35

Using rcParams you can show grid very easily as follows

plt.rcParams['axes.facecolor'] = 'white'
plt.rcParams['axes.edgecolor'] = 'white'
plt.rcParams['axes.grid'] = True
plt.rcParams['grid.alpha'] = 1
plt.rcParams['grid.color'] = "#cccccc"

If grid is not showing even after changing these parameters then use

plt.grid(True)

before calling

plt.show()

edited Jul 04 '19 at 22:41

ImportanceOfBeingErnest

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answered Mar 24 '17 at 19:28

Ani

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oxidworks · Answer 4 · 2016-10-03T12:34:08.057

Here is a small example how to add a matplotlib grid in Gtk3 with Python 2 (not working in Python 3):

#!/usr/bin/env python
#-*- coding: utf-8 -*-

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk
from matplotlib.figure import Figure
from matplotlib.backends.backend_gtk3agg import FigureCanvasGTK3Agg as FigureCanvas

win = Gtk.Window()
win.connect("delete-event", Gtk.main_quit)
win.set_title("Embedding in GTK3")

f = Figure(figsize=(1, 1), dpi=100)
ax = f.add_subplot(111)
ax.grid()

canvas = FigureCanvas(f)
canvas.set_size_request(400, 400)
win.add(canvas)

win.show_all()
Gtk.main()

How do I draw a grid onto a plot in Python?

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