Scratch Coding and Game Design for Yongsan Expat Kids, Seoul

1. Why Subplots

Subplots put several related charts on one figure so stakeholders see distribution, trend, and comparisons together instead of separate windows.

2. Grid Basics

plt.subplots(nrows, ncols, figsize=...) returns a figure and a 2D axes array. For a 2×2 grid:

• ax[0, 0] — top-left
• ax[0, 1] — top-right
• ax[1, 0] — bottom-left
• ax[1, 1] — bottom-right

3. Synthetic 2×2 Demo

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 10, 100)
y = np.sin(x)

fig, ax = plt.subplots(2, 2, figsize=(8, 6))

ax[0, 0].plot(x, y, color="b")
ax[0, 0].set_title("Line Plot")

ax[0, 1].scatter(x, y, color="r")
ax[0, 1].set_title("Scatter Plot")

random_data = np.random.randn(200)
ax[1, 0].hist(random_data, bins=20, color="g")
ax[1, 0].set_title("Histogram")

categories = ["A", "B", "C"]
values = [5, 7, 3]
ax[1, 1].bar(categories, values, color="m")
ax[1, 1].set_title("Bar Chart")

plt.tight_layout()
plt.show()

plt.tight_layout() reduces label collisions between adjacent cells.

4. E-Commerce 2×2 Dashboard

import pandas as pd

df = pd.read_csv("ecommerce_orders.csv", parse_dates=["Order Date"])
fig, ax = plt.subplots(2, 2, figsize=(10, 8))

ax[0, 0].hist(df["Revenue"], bins=30, color="g")
ax[0, 0].set_title("Revenue Distribution")

monthly = df.set_index("Order Date")["Revenue"].resample("ME").sum()
ax[0, 1].plot(monthly.index, monthly.values, color="r")
ax[0, 1].set_title("Monthly Revenue Trend")

ax[1, 0].hist(df["Delivery Days"], bins=10, color="m")
ax[1, 0].set_title("Delivery Days Distribution")

ax[1, 1].hist(df["Customer Rating"], bins=10, color="b")
ax[1, 1].set_title("Customer Rating Distribution")

plt.tight_layout()
plt.show()

5. sharey

sharey=True aligns y-scales across columns and shows tick labels only on the leftmost subplot; sharey=False (default) gives each panel its own scale.

fig, ax = plt.subplots(1, 2, sharey=True, figsize=(8, 4))
ax[0].plot([1, 2, 3], [0.2, 0.5, 0.8])
ax[0].set_title("First Subplot (Y-Labels Shown)")
ax[1].plot([1, 2, 3], [0.3, 0.4, 0.9])
ax[1].set_title("Second Subplot (Y-Labels Shared)")
plt.show()