Guys, I have a stream of data coming out of @Steve-Mcl excellent Buffer-parser node. Some of this I grab and set as Global/FLow Variables for other nodes/flows to access. I need to do some basic arithmetic - i get given amps and volts and need to multply them out to get an actual charge rate - obv…

Yep i have been playing with that - but my inverters report Voltage and Current only - so then i need to multiply those out to perform the calculation of Watts - could not see anywhere to do that ? I then feed the output of the buffer-parser to a change node that sets some Globals etc. Would be ni…

It is a relatively palatable bullet. msg.payload.watts = msg.payload.volts * msg.payload.amps

Yep thanks - thought one of the JSONATA gurus might jump in. Thanks Again Colin Craig

Hard to say what the JSONata would be without any data. If just a two properties in payload it would be $$.payload.volts * $$.payload.amps if you want to apply it to an object/array the please supply an example.

thanks mate, Here is what it looks like after they are spit out of the Buffer parser node [image] Just playing with what you have given me in a change node now thanks Craig

[image] craigcurtin: $round($$.msg.values[0] * $$.msg.values[2], 2) The msg is not needed $$ references the msg root. $round($$.values[0] * $$.values[2], 2) You can omit the $$ to, as you are already in message root. I reference $$ as habit, as when mapping or in a function you would need $…

Aah - still a babe with JSONATA - thanks for the tip Craig

Just because jsonata uses less code characters than the equivalent javascript code, it does not necessarily mean that it runs faster or more efficiently... Also, when you revisit the flow a few months later, which is easier to follow; jsonata or properly commented javascript? Just some things to c…

Hey Paul. I'm sure you know I share that sentiment but I stopped harping on about it at the risk of sounding like a broken record :wink: However, as @craigcurtin appears to be very keen and eager to learn I thought I'd chime in. I find the whole JSONata thing a bit odd. There are (according to the…

Hey Guys, Thanks for chiming in (both of you) - very much appreciate the support and guidance. I am usng this "dabbling" in JSONata as a bit of a learning exercise - but it is definitely a struggle - particularly when trying to translate JSONata resources into Node Red. I spent more than an hour …

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Whats the node red low code way to do basic maths on incoming data?

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craigcurtin 4 September 2021 06:06 8

I got it after your hint thanks

$round($$.msg.values[0] * $$.msg.values[2], 2)

Craig

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Whats the node red low code way to do basic maths on incoming data?

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