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kdbq-lang

Create a Boolean column displaying comparison between 2 other columns in kdb+

I'm currently learning kdb+/q. I have a table of data. I want to take 2 columns of data (just numbers), compare them and create a new Boolean column that will display whether the value in column 1 is greater than or equal to the value in column 2.

I am comfortable using the update command to create a new column, but I don't know how to ensure that it is Boolean, how to compare the values and a method to display the "greater-than-or-equal-to-ness" - is it possible to do a simple Y/N output for that?

Thanks.

Solution 
  • / dummy data
q) show t:([] a:1 2 3; b: 0 2 4)
    a b
    ---
    1 0
    2 2
    3 4

/ add column name 'ge' with value from b>=a
q) update ge:b>=a from t
    a b ge
    ------
    1 0 0
    2 2 1
    3 4 1