How to set "step" on axis X in my figure in Matplotlib Python 2.6.6?

To set step on X-axis in a figure in Matplotlib Python, you can control the tick positions and labels using several methods. This allows you to customize how data points are displayed along the X-axis.

Using set_xticks() and set_xticklabels()

The most direct approach is to use set_xticks() to define tick positions and set_xticklabels() to set custom labels ?

import matplotlib.pyplot as plt

plt.rcParams["figure.figsize"] = [7.00, 3.50]
plt.rcParams["figure.autolayout"] = True

x = [1, 2, 3, 4]
y = [1.2, 1.9, 3.1, 4.2]

plt.plot(x, y)
ax1 = plt.subplot()
ax1.set_xticks(x)
ax1.set_xticklabels(["one", "two", "three", "four"], rotation=45)

plt.show()

[Displays a plot with custom X-axis labels "one", "two", "three", "four" rotated at 45 degrees]

Using plt.xticks() Method

You can also use plt.xticks() for a more concise approach ?

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5, 6]
y = [2.1, 3.2, 1.8, 4.5, 2.7, 3.9]

plt.figure(figsize=(8, 4))
plt.plot(x, y, marker='o')

# Set custom step and labels
plt.xticks([1, 3, 5], ['Jan', 'Mar', 'May'])
plt.ylabel('Values')
plt.title('Custom X-axis Steps')

plt.show()

[Displays a plot with X-axis ticks only at positions 1, 3, and 5 with labels "Jan", "Mar", "May"]

Setting Regular Step Intervals

For regular intervals, you can use range() to create evenly spaced ticks ?

import matplotlib.pyplot as plt

x = range(0, 21)  # 0 to 20
y = [i**2 for i in x]

plt.figure(figsize=(10, 5))
plt.plot(x, y)

# Set ticks every 5 units
plt.xticks(range(0, 21, 5))  # 0, 5, 10, 15, 20
plt.xlabel('X Values')
plt.ylabel('Y Values')
plt.title('Regular Step Intervals')

plt.show()

[Displays a quadratic plot with X-axis ticks at 0, 5, 10, 15, and 20]

Key Parameters

• positions − List or array of tick positions
• labels − List of custom labels for each tick
• rotation − Angle to rotate tick labels (useful for long labels)
• fontsize − Size of tick label text

Conclusion

Use set_xticks() and set_xticklabels() for precise control over X-axis steps and labels. For simpler cases, plt.xticks() provides a convenient shorthand method.