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* replace underscores with dashes and redirect old urls * tldrs, listicles, and in-site cross-linking * add canonical tags to all pages * changelog * shorten into Co-authored-by: Abubakar Abid <abubakar@huggingface.co>
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State in Blocks
We covered State in Interfaces, this guide takes a look at state in Blocks, which works mostly the same.
Global State
Global state in Blocks works the same as in Interface. Any variable created outside a function call is a reference shared between all users.
Session State
Gradio supports session state, where data persists across multiple submits within a page session, in Blocks apps as well. To reiterate, session data is not shared between different users of your model. To store data in a session state, you need to do three things:
- Create a
gr.State()object. If there is a default value to this stateful object, pass that into the constructor. - In the event listener, put the
Stateobject as an input and output. - In the event listener function, add the variable to the input parameters and the return value.
Let's take a look at a game of hangman.
$code_hangman $demo_hangman
Let's see how we do each of the 3 steps listed above in this game:
- We store the used letters in
used_letters_var. In the constructor ofState, we set the initial value of this to[], an empty list. - In
btn.click(), we have a reference toused_letters_varin both the inputs and outputs. - In
guess_letter, we pass the value of thisStatetoused_letters, and then return an updated value of thisStatein the return statement.
With more complex apps, you will likely have many State variables storing session state in a single Blocks app.
Learn more about State in the docs.