Saving to PNG, SVG, PDF in Matplotlib - Step-by-Step Execution

Concept Flow - Saving to PNG, SVG, PDF

Create plot with matplotlib

↓

Choose file format: PNG, SVG, PDF

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Call savefig() with filename and format

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File saved on disk

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Use saved file for reports, presentations, or web

You first create a plot, then pick a file format, save it using savefig(), and finally get a file you can use anywhere.

Execution Sample

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.savefig('plot.png')
plt.savefig('plot.svg')
plt.savefig('plot.pdf')

This code draws a simple line plot and saves it three times in PNG, SVG, and PDF formats.

Execution Table

Step	Action	Filename	Format Detected	Result
1	Create plot	-	-	Line plot with points (1,4), (2,5), (3,6) created
2	Save plot	plot.png	PNG	File 'plot.png' saved as PNG image
3	Save plot	plot.svg	SVG	File 'plot.svg' saved as SVG vector image
4	Save plot	plot.pdf	PDF	File 'plot.pdf' saved as PDF document
5	End	-	-	All files saved successfully

💡 All savefig calls completed, files saved in specified formats

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
plot_object	None	Line plot created	Line plot unchanged	Line plot unchanged	Line plot unchanged	Line plot unchanged
filename	None	None	plot.png	plot.svg	plot.pdf	plot.pdf
format	None	None	PNG	SVG	PDF	PDF

Key Moments - 3 Insights

Why do we not need to specify the format explicitly in savefig()?

Matplotlib detects the format from the file extension in the filename, as shown in execution_table steps 2-4.

What happens if you call savefig() multiple times without creating a new plot?

The same plot is saved multiple times in different formats or files, as seen in steps 2-4 where the plot_object stays unchanged.

Can you save a plot before creating it?

No, the plot must exist first (step 1) before saving; otherwise, savefig() will save an empty or error plot.

Visual Quiz - 3 Questions

Look at the execution_table, what format is detected when saving 'plot.svg'?

A PNG

B SVG

C PDF

D JPEG

💡 Hint

Check the 'Format Detected' column in row 3 of execution_table.

At which step does the plot get created?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the 'Action' column in execution_table for when the plot is created.

If you change the filename to 'myplot.pdf' in step 2, what format will matplotlib save?

A PDF

B SVG

C PNG

D Cannot save

💡 Hint

Matplotlib uses the file extension to detect format as shown in execution_table steps 2-4.

Concept Snapshot

matplotlib savefig() saves plots to files.
File format is guessed from filename extension.
Common formats: PNG (image), SVG (vector), PDF (document).
Call plt.savefig('filename.ext') after plotting.
Files can be used in reports or presentations.

Full Transcript

This visual execution shows how to save matplotlib plots to PNG, SVG, and PDF files. First, a simple line plot is created with plt.plot(). Then, plt.savefig() is called three times with different filenames ending in .png, .svg, and .pdf. Matplotlib detects the file format from the extension and saves the plot accordingly. The execution table tracks each step, showing the action, filename, detected format, and result. The variable tracker shows the plot object remains the same while filename and format change with each save. Key moments clarify that the format is detected from the filename, the plot must exist before saving, and multiple saves reuse the same plot. The quiz tests understanding of format detection, plot creation step, and effect of changing filename. The snapshot summarizes the main points for quick recall.