For generating a new column from two given columns, how can I reference these columns by index?

[halloleo]

I have rather often sheets where a few headers are not unique, so in order to generate new columns (via the = command) I need to reference given columns via their index and not by name.

How can I do this?

[geekscrapy]

Hey!

One (longish) way to do this is with
=visibleCols[1].getValue(row)

This gets the visible column by index (in this case 1), and then gets the raw value of that row. There are other ways to get the data, based on what you want and speed (getTypedValue, getDisplayValue etc.), see here: https://www.visidata.org/docs/api/columns#visidata.Column.getValue

[halloleo]

Cool! I'll keep that in mind. Speaking of an index on the Columns sheet: Is there a way to automatically add this index (so that not everytime I look at my columns list I have to press i to add the numbering)?

It's just a question. - After al in VisiData are so many things customisable... 😄

[saulpw]

You can't currently, but I've wondered about an option for a 'row number' column fixed at the far left of the window. Then you could set the option on all ColumnsSheet. Do you want it for readability?

[halloleo]

Well, yes and no: Yes, because in sheets with lots of columns it helps you to know better where which column is, but it also helps a lot for interoperability with other tools:

When I need to do some processing in external tools (which expect column indexes) I have started to use vd as a "column viewer". (In the past I used csvcut -n for this, but vd in a new xterm seems to be more practical.)

I hope this makes sense.

[saulpw]

It does, but I'm not sure what you do with that column number. Do you type it manually into one of those tools in another window? Or is there some way you need the column number to be more than cosmetic (like usable in a VisiData expression)?

[halloleo]

My main use is indeed only to use it somewhere else by typing or to check columns are in the right place.

But I think it can come in handy inside VisiData as well: Sometimes you don't care about column names, but more about column indexes: Say you have column sequences like Street, City, State, AltStreet, AltCity, AltState, ClientStreet, ClientCity, ClientState, then you know State is always Street index + 2.