x axis questions

Support questions for Flow CSV Viewer and Editor.
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PlasmaHH
Posts: 2
Joined: Thu Mar 21, 2024 10:22 pm

x axis questions

Post by PlasmaHH »

Hi, I am trying out the csv viewer and got quite quick results, loving the way it autodetects groups etc.

However I am a bit confused about the handling of x-axis. Even though I have enabled saving the setting for variables in the project files, the setting of using a variable as an x-axis is not saved, I always have to after opening reset the x axis for the variable I want. Also I am using seconds since epoch as a float for it, is there a way that it is automatically converted into a proper (utc?) timestamp.

PS: it would also be very helpful if one could autocomplete variable names in the formula editor, or at least copy them from elsewhere, ours get really complicated.
Waveworks
Posts: 163
Joined: Thu Sep 05, 2019 1:05 pm

Re: x axis questions

Post by Waveworks »

Hello,

You're correct, Flow doesn't store the X axis settings, which clearly it should. I'll fix it for the next version. Sorry about the inconvenience!

Flow doesn't have a datetime type, but as a matter of fact there is an undocumented function for turning a Unix timestamp (milliseconds since Jan 1, 1970) into a string of the format yyyy-mm-dd hh:mm:ss. The name of the function is str_datetime. So if your time variable is time (in seconds since epoch), you'd write:

Code: Select all

timestamp = str_datetime(time * 1000)
Note that the name of this function may change in future version - that's why it's undocumented.

In Flow CSV Editor, the paid version, it should be possible to double-click a variable name and copy it, so you can paste it into your formula afterwards. In Flow CSV Viewer, this isn't possible, but a workaround could be to open the CSV file and copy the names from there. Not ideal obviously, but possibly helpful... Anyway, autocompletion of variable names sounds like a great idea, so I'll add it to the list. Thanks!

Best regards,
Gustaf
PlasmaHH
Posts: 2
Joined: Thu Mar 21, 2024 10:22 pm

Re: x axis questions

Post by PlasmaHH »

Thank you very much, that datetime is very helpful and I guess a lot of people would not mind it being an official feature.

Another question regarding x axis: Is there a way to make something a "true x axis" and not just display the values? I have lots of data where the time between points varies a lot (e.g. for saving space two equal points would not be output) and it makes interpretation of the data somewhat difficult.
Waveworks
Posts: 163
Joined: Thu Sep 05, 2019 1:05 pm

Re: x axis questions

Post by Waveworks »

Glad it helped! No unfortunately not, and that's by far the most requested feature - quite understandably. It's a bit complicated to implement however, because the entire caching mechanism that makes Flow quite fast to plot big data files depends on a fixed data point width. But it will come, eventually! I'll not yet another request for this.

Best regards,
Gustaf
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