Select rows based of multiple conditions

[#1]

Hello,

I'm trying to select rows where either the second or third column have a value below 10^-9, or if there is a missing value in the 4th column. The problem appears to be with the less than operator and I cannot figure out why.

Example table:

Col1	Col2	Col3	Col4
1	0.00000059	0.000000308	A
2	4.08e-9	-8.1e-11	B
3	-1.11e-10	1.02e-10

Here's the code:

dtColNames = dt << get ColumnNames("String");
val = 10^-9;
dt << Select Where((dt:dtColNames[2]<val | dt:dtColNames[3]<val ) | ismissing(dt:dtColNames[4]));

If I simplify this down to the following:

dtColNames = dt << get ColumnNames("String");
val = 10^-9;
dt << Select Where(dt:dtColNames[2]<val );

nothing is selected, when row 3 should be.

[#2 · Accepted solution]

A character string is not a column name or reference. You need to convert the string to a column reference.

dt << Select Where( Column( dt, dtColNames[2] )[] < val | Column( dt, dtColNames[3] )[] < val | ismissing( Column( dt, dtColNames[4] )[] ));

[#3]

Ah! Thanks!