Date locators for tick spacing in Matplotlib - Mini Project: Build & Apply

Date locators for tick spacing

📖 Scenario: You are analyzing daily sales data for a small shop over one month. You want to create a line chart showing sales over time. To make the chart easy to read, you will set the spacing of date ticks on the x-axis using date locators.

🎯 Goal: Create a line plot of sales over dates and use matplotlib.dates date locators to set the tick spacing on the x-axis to show every 7 days.

📋 What You'll Learn

Create a list of dates for 30 days starting from 2024-01-01

Create a list of sales numbers for each date

Use matplotlib.dates DayLocator with interval 7 to set tick spacing

Plot the sales data with dates on the x-axis

Display the plot with properly spaced date ticks

💡 Why This Matters

🌍 Real World

Date locators help make time series charts easier to read by controlling how often dates appear on the axis. This is useful in sales, weather, finance, and many other fields.

💼 Career

Data scientists and analysts often visualize time series data. Knowing how to set date tick spacing improves the clarity and professionalism of reports and dashboards.

1

Create the sales data and dates

Create a list called dates with 30 consecutive dates starting from datetime.date(2024, 1, 1). Create a list called sales with these exact values: [20, 22, 19, 24, 30, 28, 25, 27, 29, 31, 33, 35, 34, 32, 30, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14].

Matplotlib

import datetime
# Create the list 'dates' with 30 consecutive dates starting from 2024-01-01
# Create the list 'sales' with the given values
# Your code here

Need a hint?

Use a list comprehension with datetime.timedelta(days=i) to create consecutive dates.

2

Import date locator for tick spacing

Import matplotlib.pyplot as plt and import DayLocator from matplotlib.dates.

Matplotlib

import datetime

import matplotlib.pyplot as plt
from matplotlib.dates import DayLocator
# Your code here

Need a hint?

Use import matplotlib.pyplot as plt and from matplotlib.dates import DayLocator.

3

Set the date locator for tick spacing

Create a variable called locator and set it to DayLocator(interval=7). Then create a plot with plt.plot(dates, sales). Use plt.gca().xaxis.set_major_locator(locator) to set the x-axis major ticks to every 7 days.

Matplotlib

import datetime

import matplotlib.pyplot as plt
from matplotlib.dates import DayLocator

# Create a DayLocator with interval 7 and assign to 'locator'
# Plot the sales data against dates
# Set the x-axis major locator to 'locator'
# Your code here

Need a hint?

Use DayLocator(interval=7) to show ticks every 7 days.

4

Display the plot

Add plt.show() to display the plot with date ticks spaced every 7 days.

Matplotlib

import datetime

import matplotlib.pyplot as plt
from matplotlib.dates import DayLocator

# Display the plot
# Your code here

Need a hint?

Use plt.show() to display the plot window.