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Practice

Plotting with plt.plot()

The plt.plot() function is one of the most fundamental and versatile tools in Matplotlib.

It creates line plots by connecting data points along the x- and y-axes.

If you only pass one list of values, Matplotlib assumes they represent the y-values and automatically generates x-values starting from 0.


Plotting X and Y Values​

When both x and y values are provided, Matplotlib connects each pair of points with a line by default.

Plotting X and Y Values
import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y = [10, 20, 25, 30, 40]

plt.plot(x, y)
plt.title("Sample Line Plot")
plt.xlabel("X-axis")
plt.ylabel("Y-axis")
plt.show()
  • The order of x and y matters. Both lists must be the same length.
  • If the plot looks wrong, check that your data is properly aligned.

Plotting Only Y Values​

You can also plot a list of values without specifying x.

In that case, the x-axis will automatically be set to [0, 1, 2, ...].


Plotting Only Y Values
y = [5, 9, 4, 7]

plt.plot(y)
plt.title("Auto X-Axis")
plt.ylabel("Y Values")
plt.show()

This method is great for quick visual checks of any one-dimensional data, especially during early exploration.

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