Step plot in matplotlib

Sample data

# Data
x = [1, 2, 3, 4, 5, 6, 7]
y = [10, 10, 14, 14, 12, 16, 16]

Step plot in matplotlib with step

A step plot connects points with horizontal and vertical segments instead of a diagonal line, which is more accurate for values that stay constant and then jump at a discrete point, such as a price change or an inventory count. Use ax.step with the same syntax as a regular plot.

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.step(x, y)

# plt.show()

Step position

The where argument controls where the vertical jump happens relative to each point: "pre" (default) steps before the point, "post" steps after it, and "mid" places the jump halfway between two points.

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.step(x, y, where = "post")

# plt.show()

Colors

Customize the line the same way as in a regular line plot, with color, linewidth and linestyle.

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.step(x, y, color = "#C44E52", linewidth = 2)

# plt.show()

Markers

Add marker to also mark the actual data points on top of the steps.

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.step(x, y, marker = "o")

# plt.show()

Filled step plot

To shade the area under a step plot, use fill_between with a matching step argument instead of ax.fill, which only interpolates diagonally between points.

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
ax.step(x, y, where = "post")
ax.fill_between(x, y, step = "post", alpha = 0.3)

# plt.show()