Re: [Gnuplot-info] columns with time format as "y"

[Ethan M. <eam...@gm...>]

On Monday, 20 April 2020 11:30:03 PDT co...@tr... wrote:
> 
> Hello All,
> 
> I need help with the following problem:
> 
> Let's say my input data look like (columns delimited by \t):
> 
>    2019-04-16 20:30:00	30522	5
>    2019-04-16 20:31:00	30523	6
>    2019-04-16 20:32:00	30524	7
>    2019-04-16 20:33:00	30525	8
>    2019-04-16 20:34:00	30526	9
>    2019-04-16 20:35:00	30527	10
>    2019-04-16 20:36:00	30528	11
>    2019-04-16 20:37:00	30529	12
>    2019-04-16 20:38:00	30530	13
>    2019-04-16 20:39:00	30531	14
> 
> Column 1 & 2 (space separated) considered as date/time.
> 
> Plotting Col. 3 or 4 against date/time works fine:
> 
>    set xdata time
>    set timefmt "%Y-%m-%d\t%H:%M:%S"
>    set format x "%d.%m. %H:%M"
>    plot 'my_file.txt' using 1:3 title "col 3" axis x1y1 with linespoints
>      pt7 lc 4, '' using 1:4 title "col 4" axis x1y1 with linespoints
>      pt7 lc 7
> 
> Special feature: Although columns 1 and 2 *together* give the timestamp, 
> only "1:..." is given for "using" statement. This method is often found 
> in examples.
> 
> But now I would like - don't ask me why - to plot the timestamp against 
> column 3, i.e. column 3 as "x" and the timestamp (columns 1 & 2) as "y".
> 
> I was trying:
> 
>    set ydata time "%Y-%m-%d\t%H:%M:%S"
>    set timefmt "%Y-%m-%d\t%H:%M:%S"
>    set format y "%d.%m. %H:%M"
>    plot 'my_file.txt' using 3:1 title "col 3" axis x1y1 with
>      linespoints pt7 lc 4
> 
> Result: only date is used for plotting "y", time ignored!

Replace the tab with a space in timefmt:

    set timefmt "%Y-%m-%d %H:%M:%S"

The space character in the format will match any whitespace sequence,
including <tab>.

	Ethan