Delete columns with for loop

yanee — Fri, 09 Jun 2023 15:58:26 GMT

Hi,

I create a for loop script to delete empty column (column contains only N/A).

It works ok except on one file, one column get deleted when it's not suppose to.

Not sure what's wrong

for (i= ncols (dt[d]),i>=1,i--,
	summarize(data table(dt[d]),temp = by(column(i)));
	if(nitems(temp) ==1 & temp[1]=="N/A",
		data table(dt[d])<< delete columns(column(i));
	);
);

Re: Delete columns with for loop

jthi — Tue, 13 Sep 2022 18:59:35 GMT

Add supporting prints inside your for loop to see what is going on with the one specific column. I usually like using Show()

Names Default To Here(1);

dt = {};

dt_u = New Table("Untitled",
	Add Rows(3),
	New Column("Column 1", Character, "Nominal", Set Values({"N/A", "N/A", "N/A"})),
	New Column("Column 2", Character, "Nominal", Set Values({"a", "", ""})),
	New Column("Column 3", Character, "Nominal", Set Values({"b", "", ""})),
	New Column("Column 4", Character, "Nominal", Set Values({"N/A", "N/A", ""}))
);
dt[1] = dt_u << get name;
d = 1;

For(i = N Cols(Datatable(dt[d])), i >= 1, i--,
	Summarize(Data Table(dt[d]), temp = by(Column(i)));
	If(i == 3,
		show(temp);
	);
	If(N Items(temp) == 1 & temp[1] == "N/A",
		show(temp);
		Data Table(dt[d]) << delete columns(Column(i))
	);
);

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Delete columns with for loop

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