{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# More on Widgets: Using Interact \n", "\n", "The `interact` function [`ipywidgets.interact`](https://ipywidgets.readthedocs.io/en/latest/examples/Using%20Interact.html) is the quickest way to create user interface controls in code. It is the easiest way to get up and running! \n" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "import ipywidgets as widgets" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Basic `interact`\n", "\n", "At the most basic level, `interact` autogenerates controls for function arguments, and then calls the function with those arguments when you manipulate the controls interactively. To use `interact`, you need to define a function that you want to explore. " ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "def f(x):\n", " return 3*x" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "When you pass this function as the first argument to `interact` along with an integer keyword argument (`x=10`), a slider is generated and bound to the function parameter." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "widgets.interact(f, x=10);" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "If you pass `True` or `False`, `interact` will generate a checkbox:" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "widgets.interact(f, x=True);" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "If you pass a string, `interact` will generate a `Text` field." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "widgets.interact(f, x='Hello!');" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "`interact` can also be used as a decorator. This allows you to define a function and interact with it in a single shot. As this example shows, `interact` also works with functions that have multiple arguments." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "@widgets.interact(x=True, y=1.0)\n", "def g(x, y):\n", " return (x, y)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Fixing arguments with `fixed`\n", "\n", "There are times when you may want to explore a function using `interact`, but fix one or more of its arguments to specific values. This can be accomplished by wrapping values with the `fixed` function." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "def h(p, q):\n", " return (p, q)" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "widgets.interact(h, p=5, q=widgets.fixed(20));" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Widget abbreviations\n", "\n", "When you pass an integer-valued keyword argument of `10` (`x=10`) to `interact`, it generates an integer-valued slider control with a range of `[-10,+3*10]`. In this case, `10` is an *abbreviation* for an actual slider widget:\n", "\n", "```python\n", "IntSlider(min=-10,max=30,step=1,value=10)\n", "```\n", "\n", "In fact, we can get the same result if we pass this `IntSlider` as the keyword argument for `x`:" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "widgets.interact(\n", " f, x=widgets.IntSlider(min=-10, max=30, step=1, value=10)\n", ");" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "This examples clarifies how `interact` proceses its keyword arguments:\n", "\n", "1. If the keyword argument is a `Widget` instance with a `value` attribute, that widget is used. Any widget with a `value` attribute can be used, even custom ones.\n", "2. Otherwise, the value is treated as a *widget abbreviation* that is converted to a widget before it is used.\n", "\n", "The following table gives an overview of different widget abbreviations:\n", "\n", "
Keyword argument | Widget |
`True` or `False` | Checkbox |
`'Hi there'` | Text |
`value` or `(min,max)` or `(min,max,step)` if integers are passed | IntSlider |
`value` or `(min,max)` or `(min,max,step)` if floats are passed | FloatSlider |
`['orange','apple']` or `[('one', 1), ('two', 2)]` | Dropdown |