(quickstart)= # Getting started ## Try it online ```{eval-rst} Try Pyodide in a `REPL <../console.html>`_ directly in your browser (no installation needed). ``` ## Setup To include Pyodide in your project you can use the following CDN URL: ```text {{PYODIDE_CDN_URL}}pyodide.js ``` You can also download a release from [GitHub releases](https://github.com/pyodide/pyodide/releases) or build Pyodide yourself. See {ref}`downloading_deploying` for more details. The `pyodide.js` file defines a single async function called {any}`loadPyodide ` which sets up the Python environment and returns {js:mod}`the Pyodide top level namespace `. ```pyodide async function main() { let pyodide = await loadPyodide(); // Pyodide is now ready to use... console.log(pyodide.runPython(` import sys sys.version `)); }; main(); ``` ## Running Python code Python code is run using the {any}`pyodide.runPython` function. It takes as input a string of Python code. If the code ends in an expression, it returns the result of the expression, translated to JavaScript objects (see {ref}`type-translations`). For example the following code will return the version string as a JavaScript string: ```pyodide pyodide.runPython(` import sys sys.version `); ``` After importing Pyodide, only packages from the standard library are available. See {ref}`loading_packages` for information about loading additional packages. ## Complete example Create and save a test `index.html` page with the following contents: ```html-pyodide Pyodide test page
Open your browser console to see Pyodide output ``` ## Alternative Example ```html

You can execute any Python code. Just enter something in the box below and click the button.

Output:

``` ## Accessing Python scope from JavaScript All functions and variables defined in the Python global scope are accessible via the {any}`pyodide.globals` object. For example, if you run the code `x = numpy.ones([3,3])` in Python global scope, you can access the global variable `x` from JavaScript in your browser's developer console with `pyodide.globals.get("x")`. The same goes for functions and imports. See {ref}`type-translations` for more details. ```{eval-rst} You can try it yourself in the browser console. Go to the `Pyodide REPL URL <../console.html>`_ and type the following into the browser console:: ``` ```pyodide await pyodide.loadPackage("numpy"); pyodide.runPython(` import numpy x=numpy.ones((3, 4)) `); pyodide.globals.get('x').toJs(); // >>> [ Float64Array(4), Float64Array(4), Float64Array(4) ] ``` You can assign new values to Python global variables or create new ones from Javascript. ```pyodide // re-assign a new value to an existing variable pyodide.globals.set("x", 'x will be now string'); // add the js "alert" function to the Python global scope // this will show a browser alert if called from Python pyodide.globals.set("alert", alert); // add a "square" function to Python global scope pyodide.globals.set("square", x => x*x); // Test the new "square" Python function pyodide.runPython("square(3)"); ``` ## Accessing JavaScript scope from Python The JavaScript scope can be accessed from Python using the `js` module (see {ref}`type-translations_using-js-obj-from-py`). We can use it to access global variables and functions from Python. For instance, we can directly manipulate the DOM: ```python import js div = js.document.createElement("div") div.innerHTML = "

This element was created from Python

" js.document.body.prepend(div) ```