timex | timex is a usefull golang time toolkit | Web Framework library

I think this a formatting issue- If TimeY is "" and TimeX is "", then Total = TimeValue(TimeY) - TimeValue(TimeX) is 0.

0 in time format is 0:0:00 and 0 in date format is 00/01/1900

One solution to this is to include an if statement that checks that there are not blank cells

You need to convert to timestamp using to_timestamp and then to the desired format using date_format:

onChildAdded is triggered for each child node when you add the listener, and only then triggered when an additional child is added. So what you're seeing is the expected behavior.

Also see the documentation on listening for child events, which says about onChildAdded:

Retrieve lists of items or listen for additions to a list of items. This callback is triggered once for each existing child and then again every time a new child is added to the specified path. The DataSnapshot passed to the listener contains the the new child's data.

I don't think you can based on this: https://hexdocs.pm/phoenix_live_view/Phoenix.LiveComponent.html#module-managing-state

Components run inside the LiveView process, but may have their own state and event handling.

I believe both "child component" and parent share the same process.

I made a few small edits to your sample dataframe based on my comment above:

① You don’t need to wrap a single atom with a tuple in message passing, any term works well
② The reference provided by Adam in the comments is definitely worth reading, as well as the whole book
③ It could be extremely helpful if you were sharing the error message you’ve got with the uncommented messages passed

The issue is Kernel.send/2 sends is normal message, :info in elixir terminology, which is asynch.

Each process has a mailbox, that gets processed one-by-one message when receive/1 is called. Inside the process, all the code is executed synchronously. So your :print handler basically does not do what you think it does, instead it sends a couple of messages to self() and immediately executes print_month/3, before VM had ever any chance to pass the messages to the process.

I would suggest instead of sending messages for everything, do synchronous parts as they are to be done: with functions. Somewhat along these lines.

Here are some thoughts/suggestions that might be helpful.

First, if you wish to look at maximum value for Concentration, I would not have this column be of character type. Instead, would make it numeric, and use NA for missing values. The first mutate sets that up.

After grouping, you can use mutate and case_when for your various situations. You can access the Time of maximum concentration through:

You could use postgres CURRENT_TIMESTAMP - INTERVAL '600 seconds' instead of using an elixir variable inside the query.

Also, I see you commented that you want to filter by updated_at but your query is actually filtering by inserted_at.

I solved my problem. I just had to reset numX nameX timeX lineY each time I switched to leaderboard

Ok, so we've learnt a lesson, global state is a bad thing ...

Ok, since I spent some time putting the example together, I'd post it to demonstrate a basic concept of shared state.

This example creates a LeaderBoardModel which is shared between the main views. This allows the state to be shared between different aspects of your code, without the need to explicitly understand how it actually works - the model becomes a self contained unit of work and can manage it's own state.

Another aspect here, is trying to keep your paint path as fast as possible - so, even in this example, sorting and splitting the list could be considered for optimisation ... but we're not trying to achieve 200fps ... so, balancing...