Sharing Data between Dash Callbacks

[@HaHa-gy5vg]

You are on of the few people I genuinely admire on this earth. My hope is more people catch on to how generous it is of you to share your curated knowledge AND use it to help humans and animals alike. Thank you for sharing these gifts and please know it is making a huge difference.

[@CharmingData]

Thank you for your kind words, @king Voss

[@vinaygh90]

Couldn’t agree more. Thank you, Adam, for everything you do. I have come a long way watching your videos - from no python experience to hosting my first multi tab fancy dashboard to analyze my work results.

[@andrw3]

You're a life saver! Every time I try to do something in Plotly and Dash, I come up with one of your videos and end up solving it. Thank you very much!

[@CharmingData]

Thank you Andrés. I'm glad my tutorials are helpful.

[@kvjayalath]

That is exact the same with me. Every dash problems ended up here and it is solved !!. Thanks for you time, effort and energy you put in to this.

[@CharmingData]

@@kvjayalath Thank you Kasun

[@luchaoqi]

Thanks so much for your continuing contributions to the dash community!

[@CharmingData]

You're welcome Luchao

[@haozeng5003]

Thank you soooooo much!! I definitely won't be able to finish my final year project without you

[@EyeofEthiopia]

Thanks for your time putting this together and share with us.

[@yaroslavhavrysh5955]

Just subscribed to the Plotly community thanks to you and your videos here on KZbin. You are helping me grow a lot Sir, thank you very much 🙂

[@CharmingData]

You are welcome, Yaroslav. I'm happy you're learning a lot.

[@xnaxx900]

Amazing content, very clear and easy to follow. Thank you for all you do!

[@sajayagopi]

Thank you so much. I was using Global variable to store data. This is so much better.

[@jesusmtz29]

Just what i was looking for

[@swaidaslam8266]

Thanks for sharing!

[@mohitahuja1141]

Thanks so much for another kick ass video :)

[@octo3010]

Back again....nice.

[@CharmingData]

Yes, I have a lot going on in life, but I'm trying to post weekly or at least once every two weeks.

[@octo3010]

@@CharmingData thanks

[@nikhilshingadiya7798]

Long time man ❣️❣️

[@TheGao1978]

Great content. Thanks for doing this Adam! Question, what’s the difference between instantiating a data frame first and then just have the callbacks work off of that vs using dcc store? Is the data frame re-fetched from the server on every callback?

[@CharmingData]

Exactly, the data frame re-fetched from the server on every callback

[@kadirsevil191]

Thanks for sharing.I wonder if it is possible to share figure item between graph callback and download callback so that it can be used in download callback as html file

[@davidaliaga4708]

why the second function is create_graph1 if it is creating tables?

[@ehangroenewald5783]

Great explanation, is it possible to store multiple datasets in one callback, in that case once the dropdown selections are made you can immediately do the necessary steps on multiple tables in one callback. i.e. if you had to save the three datasets in this example independently (dataset1; dataset2; dataset3)

[@CharmingData]

It's possible. I think you can use three store components

[@ryansimpson2908]

Hi, thanks alot for this video. Quick question, if I wanted to upload data without user selection to be used on different pages how best would I do that? The dataframes will also be different sizes. Thank you

[@CharmingData]

hi Ryan, I'm not sure I understand your question. Can you please clarify.

[@davidaliaga4708]

What I dont undersand is, if you change the pull down you are loading the data everytime, so how does this store the data in memory?

[@CharmingData]

It stores the data in your browser, until you choose to store a different data set

[@jesusmtz29]

I noticed that I cannot serialize dictionaries with numpy arrays. I found a workaround for this but is there a design reason for this?

[@CharmingData]

Hi Jesus, No, not that I know of.

[@adityanjsg99]

Sir, for scalability, what do you recommend, Dash or React? I am a Django backend developer.

[@CharmingData]

Probably React if you already know Django, but Dash Enterprise is probably the best if you have the money

[@eam2036]

Hi everyone, Need some help, Trying to make a multipage app with a huge amount of tabs, the tabs need an input value from a button on a page, Stock/Crypto symbol button input box, then that symbol needs to be saved with ddc.store so when i click on one of the 20 tabs it keeps that symbol to use in the newly displayed tab? I cant get it to work, I have to re-click/re-enter the symbol into the input box every time i click on a new tab, I cant get the structure of the storage callback to work and then how to use that output into the tab callback.. Any help would be appreciated

[@ashwathmukundan7699]

Thank you for your videos ! Could you confirm how data can be shared between multiple tabs/layouts. Dcc.Store works well within the same layout however i'm not able to figure out how to share data between different layouts. Thanks!

[@CharmingData]

Hi Ashwath, try to put the dcc.Store in the main app.py page (where your main layout is). That should allow you to share the data stored with other tabs

[@venkat2132]

@@CharmingData so can we input the store input id to the other page layout callback as input ? in case of multi page app?

[@CharmingData]

@@venkat2132 yes. Put the DCC.store on the main page, and then use the same id on an inner page to pull data or store the data via callback. See how Ann Marie does it in this app: github.com/AnnMarieW/dash-multi-page-app-demos/tree/main/multi_page_store

[@venkat2132]

@@CharmingData what is the limit of storing data interms of number of records is it max of 100000? Because we have more data like 700000 or so..

[@jeanjean411]

Hello I have an app that interact with a ML model and returns a score when I input values through sliders but I also have a drag and drop button where I drop a dataframe and interact with my model then return a prediction. The probleme is after being used, the drag and drop button freeze my other page widgets. How can I solve this to reset the drag and drop state ? Thank you for the great video!

[@CharmingData]

hi @jeanjean411. It's really hard to give guidance without seeing the code. Are you able to post this question with the code on the Plotly forum?

[@jeanjean411]

@@CharmingData Hello, thank you for your answer. Indeed I made a post on the forum!

[@Pippa1351]

is it possible to store an object which also contains another object using dcc.Store()?

[@CharmingData]

hi Pippa, what do you mean? can you please give a simple example?

[@sajith10]

Hi Adam, thanks for the great videos! I’m new to python programming and I have already learned so much from your videos! Is it possible to create an app using dash and make it shareable only with employees on a company network? I want to create interactive plots that anyone within the company can access at anytime. Is there a way to do this using python-dash? Thanks!

[@CharmingData]

Hi Sajith, that's possible. You can deploy on the intranet. I haven't done that but it's possible. Also you can deploy it to the web and use dash authentication to generate passwords that only your colleagues will know.

[@mayurpande5415]

I have a return type of tuple that contains different lists/strings to store in the dcc.Store component, can I simply use json.dumps? Or can I just put the tuple as the value to a key in a dictionary?

[@scarfface]

Does this cause a lot of network traffic? I would think the data has to be sent back to the server for all the other callbacks that are triggered by the updated Store data, but maybe I have a misunderstanding.

[@CharmingData]

Hi Tim, not a lot, because dcc.Store actually stores the data in the client's browser, so there is no need to go back and forth with the server.

[@MauriciaJames]

I am getting the error: Callback error updating stored-adf-data data TypeError: unhashable type: 'list'....I am not sure how to rectify this issue.

[@CharmingData]

do you know what line of code you get this error on? Does the error message say?

[@MauriciaJames]

@@CharmingData I figured it out. the reason I was having the error was because multi was set to true.. Once I changed it then everything worked.

[@alikoohi8265]

I follow your videos and you are great in teaching.I just started with dash and also tableau.Can you make a video to compare these two technologies so I know to stick to which one:) At the time I know that tableau is much faster in building visualizations and much less coding is needed.But dash is more customizable and programming way of doing tasks...I dont know which one is better to choose,for a personal data science road map.

[@CharmingData]

Hi Ali, you are correct in your assessment, comparing between Dash and tableau. It depends how you intend to use data visualization in your career. If you need something which and out-of-the-box dashboards, then tableau is good. But dash is open source and offers so much flexibility and customisation that is valuable for data scientists, especially those people that want to do a lot with their dashboard

[@andurobin16]

Can you make a video about python to sql? Like when u input a code on search then the output from sql will show up

[@CharmingData]

Hi @Mulia, thank you for the suggestion. I'll add it to my list of videos to make

[@durga_indu8024]

Hey!! I watched every video and it is really informative. Could you please make a video building dash using R programming. Thank you in advance. hope this will solve my problems

[@yliu4093]

Thanks, when I share dataframe between callback, I used s=json.dumps(df) then I got an error of TypeError: Object of type DataFrame is not JSON serializable. Do you know what is the error? could we share dataframe? Thanks

[@CharmingData]

Hi. You can definitely share data with the DCC.store. but you need to make sure your data is a JSON type first, if you're going to use JSON.dumps