When applying the subplot() function in Matplotlib, its position is important

I did the reading on Day 63.

Day 62 [October 8, 2025]

I need to buckle down, as I'm still lagging on day 2's remaining goals, day 3 & 4 goals, "Day 3-4: Control structures (if-else, loops)", as well as day 5 (and 6) goals, "Day 5-6: Functions and modules", and Day 7 target (exercises) (Meta AI, personal communication, August 8, 2025). If I haven't covered this, I can't make progress on day 8 - 61 goals.

Goals:

As extracted from the 'Python for Software Development' textbook by Halvorsen (n.d.):

• The New Age of Programming ✅


• What is Python? ✅


• Introduction to Python ✅


• Interpreted vs. Compiled ✅


• Python Packages ✅


• Python Packages for Science and Numerical Computations ✅


• Python Editors ✅


• Python IDLE ✅


• Visual Studio Code ✅


• Variables ✅


• Numbers ✅


• Strings ✅


• String Input✅


• Built-in Functions✅


• Python Standard Library✅


• Using Python Libraries, Packages and Modules✅


• Python Packages✅


• Plotting in Python ✅


• Subplots✅


• Exercises


• If ... Else


• Arrays


• For Loops


• Nested


• For Loops


• While Loops


• Exercises


• Creating Functions in Python - Introduction


• Functions with multiple return values


• Exercises


• Creating Classes in Python


• The init () Function


• Exercises


• Creating Python Modules


• Exercises

Notes:

'Python for Software Development' textbook by Halvorsen (n.d.):

Today, I worked on the following exercise (Halvorsen, n.d.):

"Create sin(x) and cos(x) in 2 different plots.

You should use all the Plotting functions listed below in your code:

• plot()

• title()

• xlabel()

• ylabel()

• axis()

• grid()

• legend()

• show()"

After trial and error, here is my code:

import matplotlib.pyplot as plt

import numpy as np

xStart = 0

xEnd = 2*np.pi

increment = 0.5

x = np.arange(xStart, xEnd, increment)

y = np.sin(x)

plt.plot(x,y,'g')

plt.xlabel('x')

plt.ylabel('sin(x)')

plt.title('SINE GRAPH')

plt.subplot(2,1,1)

plt.grid()

plt.show()

x = np.arange(xStart, xEnd, increment)

y = np.cos(x)

plt.plot(x,y,'r')

plt.xlabel('x')

plt.ylabel('cos(x)')

plt.title('COSINE GRAPH')

plt.subplot(2,1,2)

plt.grid()

plt.show()

However, it is off, from what they did in their own previous similar example as shown:

import matplotlib.pyplot as plt

import numpy as np

xstart = 0

xstop = 2*np.pi

increment = 0.1

x = np.arange(xstart, xstop, increment)

y = np.sin(x)

z = np.cos(x)

plt.subplot(2,1,1)

plt.plot(x,y,'g')

plt.title('sin')

plt.xlabel('x')

plt.ylabel('sin(x)')

plt.grid()

plt.show()

plt.subplot(2,1,2)

plt.plot(x,z,'r')

plt.title('cos')

plt.xlabel('x')

plt.ylabel('cos(x)')

plt.grid()

plt.show()

---Mine was causing the plot to look funny.

I noticed that difference basically was the positioning of plt.subplot(2,1,1) and plt.subplot(2,1,2) respectively.

Rearranging mine, also solved the problem:

import matplotlib.pyplot as plt

import numpy as np

xStart = 0

xEnd = 2*np.pi

increment = 0.5

x = np.arange(xStart, xEnd, increment)

y = np.sin(x)

plt.subplot(2,1,1)

plt.plot(x,y,'g')

plt.xlabel('x')

plt.ylabel('sin(x)')

plt.title('SINE GRAPH')

plt.grid()

plt.show()

x = np.arange(xStart, xEnd, increment)

y = np.cos(x)

plt.subplot(2,1,2)

plt.plot(x,y,'r')

plt.xlabel('x')

plt.ylabel('cos(x)')

plt.title('COSINE GRAPH')

plt.grid()

plt.show()

The functions axis() and legend() were not also used in my code. Quite frankly, I have no idea what they do. I'll begin my study on these tomorrow.

Summary:

When applying the subplot() function in Matplotlib, its position is important.

References:

1. Halvorsen, H. (n.d.). Python. https://halvorsen.blog/documents/programming/python/python.php#python4