Rcparams for global defaults in Matplotlib

Introduction

Rcparams let you set default styles for all your plots. This saves time and keeps your charts looking consistent.

You want all your charts to have the same font and colors.

You need to change the size of all plot titles and labels at once.

You want to set a default figure size for every plot.

You want to change line styles or marker shapes globally.

You want to apply a theme or style to all plots without repeating code.

Syntax

Matplotlib

import matplotlib.pyplot as plt
plt.rcParams['key'] = value

Replace 'key' with the setting name like 'figure.figsize' or 'lines.linewidth'.

Value depends on the key, e.g., a tuple for size or a string for color.

Examples

Sets the default figure size to 8 inches wide and 6 inches tall.

Matplotlib

import matplotlib.pyplot as plt
plt.rcParams['figure.figsize'] = (8, 6)

Sets the default line width to 2 points for all plots.

Matplotlib

import matplotlib.pyplot as plt
plt.rcParams['lines.linewidth'] = 2

Sets the default font size to 14 for all text in plots.

Matplotlib

import matplotlib.pyplot as plt
plt.rcParams['font.size'] = 14

Sample Program

This code sets global defaults for figure size, line width, line color, and font size. Then it creates a simple line plot that uses these settings automatically.

Matplotlib

import matplotlib.pyplot as plt

# Set global defaults
plt.rcParams['figure.figsize'] = (6, 4)
plt.rcParams['lines.linewidth'] = 3
plt.rcParams['lines.color'] = 'green'
plt.rcParams['font.size'] = 12

# Create a simple plot
x = [1, 2, 3, 4]
y = [10, 20, 25, 30]
plt.plot(x, y)
plt.title('Sample Plot with Global Defaults')
plt.xlabel('X axis')
plt.ylabel('Y axis')
plt.show()

Important Notes

Changing rcParams affects all plots created after the change.

You can reset rcParams to default using plt.rcdefaults().

Use plt.rcParams.keys() to see all available settings.

Summary

Rcparams let you set global plot styles in matplotlib.

Set values by assigning to plt.rcParams['key'].

This keeps your plots consistent and saves time.