Annotation with arrows in Matplotlib - Step-by-Step Execution

Concept Flow - Annotation with arrows

Create plot

↓

Choose point to annotate

↓

Add annotation text

↓

Draw arrow from text to point

↓

Display plot with annotation

The flow shows creating a plot, selecting a point, adding annotation text, drawing an arrow to that point, and displaying the final plot.

Execution Sample

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1,2,3], [4,5,6])
plt.annotate('Point', xy=(2,5), xytext=(3,4), arrowprops=dict(facecolor='black'))
plt.show()

This code plots points and adds an annotation with an arrow pointing to (2,5).

Execution Table

Step	Action	Parameters	Effect on Plot
1	Create plot line	x=[1,2,3], y=[4,5,6]	Line with points (1,4), (2,5), (3,6) appears
2	Add annotation	text='Point', xy=(2,5), xytext=(3,4)	Text 'Point' placed at (3,4)
3	Draw arrow	arrowprops with facecolor='black'	Arrow drawn from (3,4) to (2,5)
4	Show plot	plt.show()	Plot window opens showing line, text, and arrow

💡 Plot displayed with annotation and arrow pointing to the chosen point

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
plot_data	None	Line with points (1,4),(2,5),(3,6)	Same	Same	Same
annotation_text	None	None	'Point' at (3,4)	'Point' at (3,4)	'Point' at (3,4)
arrow	None	None	None	Arrow from (3,4) to (2,5)	Arrow from (3,4) to (2,5)

Key Moments - 2 Insights

Why does the annotation text appear away from the point (2,5)?

Because xytext=(3,4) sets the text position separately from xy=(2,5), which is the arrow tip. See execution_table step 2.

What controls the arrow style and color?

The arrowprops dictionary controls arrow appearance, like facecolor='black' in step 3 of execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, at which step is the annotation text placed on the plot?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Check the 'Effect on Plot' column for when text 'Point' appears.

According to variable_tracker, what is the state of 'arrow' after Step 2?

A None

B Arrow with red color

C Arrow from (3,4) to (2,5)

D Arrow from (2,5) to (3,4)

💡 Hint

Look at the 'arrow' row under 'After Step 2' column.

If xytext was set to (2,5), where would the annotation text appear?

A At (3,4) away from the point

B At (2,5) exactly on the point

C At (1,4) the first point

D No text would appear

💡 Hint

xytext controls text position; see execution_table step 2 for current position.

Concept Snapshot

plt.annotate(text, xy, xytext, arrowprops)
- text: annotation string
- xy: point to point arrow
- xytext: text position
- arrowprops: arrow style
Use to label points with arrows on plots.

Full Transcript

This visual execution shows how to add annotations with arrows in matplotlib. First, a plot line is created with points. Then, annotation text is placed at a chosen position using xytext, while the arrow points to the data point xy. The arrow style is controlled by arrowprops. Finally, the plot is displayed showing the line, text, and arrow. Variables track the plot data, annotation text, and arrow state step-by-step. Key moments clarify why text position differs from arrow tip and how arrow appearance is set. Quiz questions test understanding of annotation placement and variable states.