There is a node, that converts string to float (value), but what I should do, if string isn’t conversible?
I mean user can enter what he wants. Firstly he entered “143.885” and it is successfuly converted to float. Now user entered “1439469837162956918268714319659284376198237569825.173569128437612983.1235719853.143719283” and this not converted to float.
I didn’t finded any documentation about this, node has one string input and one float output, no boolean to check it’s been converted. Even if it returns NaN, then i don’t know how to check if float is NaN in Blueprints.
How to figure it out?
Well, now I know when the string is bad, value will be 0. In my case that in not just OK, it is COOL, because i don’t need to make branches, when it is bad or not. But what if user entered “0.0”?
“string isnumeric”
should do the trick in blueprints.
i’m having trouble because text uses comma, and floats dont like it 
Even if we “check string if it has only numeric characters” (as it said in documentation) then it’s not guaranties that it will be successfully converted to float.
Otherwise the most common solution is to create C++ BlueprintFunction class that contains function that will convert string with check. It’s not so hard to create, it is simple algorithm.
But I wonder why there is no solution for this in the engine itself…