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scottdk's avatar
scottdk
Frequent Visitor
2 years ago
Solved

Global and Local environment effect on Expression.Evaluate.

I am was completely confused about the inconsistent results I was getting from Expression.Evaluate while taking a deeper dive into learning about global and local environments in preparation for movi...
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  • m_dekorte's avatar
    m_dekorte
    2 years ago

    Hi scottdk,

     

    As the example by AlienSx clearly illustrates, a record merge (or combination operation), will overwrite like named fields from the left operant with that of the right operant. See the docs here: Values, Record  

     

    [a = 1] & [a = 2] & [a = 3] & [a = 2]

    //result: a = 2

     

AlienSx's avatar
AlienSx
Super User
2 years ago

So it's not using the first one it finds? It's more like the second one supercedes the first?

This is how records with the same field names are combined in M

    rec_1 = [a = 1],
    rec_2 = [a = 2],
    combine12 = Record.Combine({rec_1, rec_2}), // [a = 2]
    combine21 = Record.Combine({rec_2, rec_1}) // [a = 1]