Static charts

Every time you run Python code with runCode() in JavaScript or run_code() method in Python, the code is executed in a headless Jupyter server inside the sandbox.

E2B automatically detects any plots created with Matplotlib and sends them back to the client as images encoded in the base64 format. These images are directly accesible on the result items in the execution.results array.

Here’s how to retrieve a static chart from the executed Python code that contains a Matplotlib plot.

JavaScript & TypeScript

import { Sandbox } from '@e2b/code-interpreter'
import fs from 'fs'

const codeToRun = `
import matplotlib.pyplot as plt

plt.plot([1, 2, 3, 4])
plt.ylabel('some numbers')
plt.show()
`
const sandbox = await Sandbox.create()

// Run the code inside the sandbox
const execution = await sandbox.runCode(codeToRun)

 // There's only one result in this case - the plot displayed with `plt.show()`
const firstResult = execution.results[0]

if (firstResult.png) {
  // Save the png to a file. The png is in base64 format.
  fs.writeFileSync('chart.png', firstResult.png, { encoding: 'base64' })
  console.log('Chart saved as chart.png')
}

The code in the variable codeToRun/code_to_run will produce this following plot that we’re saving as chart.png file.