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AndreLuiz's avatar
AndreLuiz
Frequent Visitor
7 years ago
Solved

Help in Query Editor with the second argument of Table.FirstN using error criteria.

Hello, I would like to use the second argument of Table.FirstN with a condition in which the function stop evaluating when an error is found. I've tried Table.FirstN(Table, each [Column1] ; [Column1...
  • Anonymous's avatar
    Anonymous
    7 years ago

    The 2nd parameter of Table.FirstN() needs to be an expression that evaluates to a whole number.

     

    BUT, you can do something like this.

    PreviousStep = //some M code here,  
    Table_with_FirstN = Table.FirstN(PreviousStep, 20),
    Conditional = //some M code here that says whether or not to apply the FirstN transformation.
    FinalTable = if Conditional = true then Table_with_FirstN else PreviousStep 
    in
    
    FinalTable 

     

  • AndreLuiz's avatar
    AndreLuiz
    7 years ago

    Thank you for the answer Chris!

    What I liked in your anwer is the simplicity and brevity in the M code.

     

    In following the brevity approach to the problem I've found that the 2nd parameter of Table.FirstN() can be any condition which evaluates to True/False. So, by trying to catch the error condition, I've came to the following solution:

     

    //Using the "try ... otherwise" clause in M
    //A cell is equal to itself unless it contains an Error
    
    SingleStep = Table.FirstN(Table, each try [Column1] = [Column1] otherwise null <> null)
    // ( try..otherwise error test )

     

    Greetings,

    André