This Matplotlib Grid lesson is for a beginner. Read the short notes, run each example, then change one name or number and run it again.
A grid draws lines at the tick marks so a reader can trace a point back to the axis.
Too many ticks make the grid noisy. Show only the ticks that matter.
Example 1: Start here
plt.grid(True) turns the grid on after the line is drawn.
ticks = [0, 25, 50, 75, 100] # a list; the values stay in this order
print(ticks)
Example 2: List the points
Matplotlib Grid draws points. Printing each pair lets you check the data before a chart library plots it.
points = [(1, 35), (2, 12), (3, 18)] # a list; the values stay in this order
for x, y in points: # repeat the indented lines once per value
print(x, y) # a comma prints each value, with a space between
Example 3: Find the highest bar
The tallest bar is the largest number. max does that lookup.
heights = [35, 12, 18] # a list; the values stay in this order
print(max(heights)) # the largest value
Example 4: Label each point
A chart label belongs with its number. zip keeps each day next to its height.
labels = ["Mon", "Tue", "Wed"] # a list; the values stay in this order
heights = [35, 12, 18] # a list; the values stay in this order
for label, height in zip(labels, heights): # repeat the indented lines once per value
print(label, height) # a comma prints each value, with a space between
plt.grid(True) turns the grid on after the line is drawn.
