Matplotlib does not draw the last line

I have a function that takes a list of tuples with float values, from the list I make two new separate lists, each containing the vertex coordinates of the triangle. Then I use matplotlib to draw the vertices.

def draw_figure(list_of_floats):
    
x_coord, y_coord = zip(*list_of_floats)
x_coord = list(x_coord)
y_coord = list(y_coord)

# print("Coordinates:")
# for item in x_coord:
#     print(item)
# for item in y_coord:
#     print(item)

# Plot the triangle
plt.plot(x_coord, y_coord)

# Set the plot limits
plt.xlim(min(x_coord) - 1, max(x_coord) + 1)
plt.ylim(min(y_coord) - 1, max(y_coord) + 1)

But instead of three lines, the library draws two. I tried adding:

 plt.plot(x_coord, y_coord, x_coord[0], y_coord[1]) 

So that it had to draw a third line to the beginning, but it did not work too.

How do I supposed to fix this?

>Solution :

Just append the initial (x,y) coordinate at the end:

import matplotlib.pyplot as plt

def draw_figure(list_of_floats):
    x_coord, y_coord = zip(*list_of_floats)
    x_coord = list(x_coord)
    y_coord = list(y_coord)

    # THIS: add initial point
    x_coord.append(x_coord[0])
    y_coord.append(y_coord[0])

    # Plot the triangle
    plt.plot(x_coord, y_coord)

    # Set the plot limits
    plt.xlim(min(x_coord) - 1, max(x_coord) + 1)
    plt.ylim(min(y_coord) - 1, max(y_coord) + 1)

I tested with the following data:

draw_figure([[1, 2], [3, -1], [2.5, 5]])