Re: multiple plot lines with plot '-'

[<pl...@pi...>]

On 05/14/12 18:27, Ethan A Merritt wrote:
> The next obvious thought is "can't we remember the values we just read
> and re-use them if necessary?". But that doesn't work either.
> Consider:
>     plot '-' using 1:2, '' using 3:4, '' using 99:100
> The first plot uses only columns 1 and 2; these values are stored
> internally and could be used again without rereading.  That's what the
> "refresh"  command does.  But the 2nd and 3rd plots use data values from
> columns we didn't use the first time and hence didn't keep.
> So those values can only be recovered by rereading.

Since this is all in one plot command , couldn't the whole line be 
parsed to find all the columns to be required by all the using clauses?

In fact isn't this already done? Are you implying that


  plot datafile using 1:2, '' using 3:4, '' using 99:100

actually reads the data file three times looking at different columns :?

thx, Peter.