I originally thought this may be the same as gnuplot - start of X series - Stack Overflow - but I think this is slightly more specific.
Since I'm interested in finding the "start of X series", so to speak - I'll try to clarify with an example; say you have this script:
# generate data
system "cat > ./inline.dat <<EOF\n\
10.0 1 a 2\n\
10.2 2 b 2\n\
10.4 3 a 2\n\
10.6 4 b 2\n\
10.8 5 c 7\n\
11.0 5 c 7\n\
EOF\n"
# ranges
set yrange [0:8]
set xrange [0:11.5]
plot "inline.dat" using 1:2 with impulses linewidth 2
If you plot it, you'll notice the data starts from 10 on x-axis:
Now, of course you can adjust the xrange - but sometimes you're interested in "relative positions" which start "from 0", so to speak. Therefore, one would like to see the data "moved left" on the x-axis, so it starts at 0. Since we know the data starts at 10.0, we could subtract that from first column explicitly:
plot "inline.dat" using ($1-10.0):2 with impulses linewidth 2
... and that basically does the trick.
But say you don't want to specify the "10.0" explicitly in the plot command above; then - knowing that it is the first element of the first column of the data which is already loaded, one would hope there is a way to somehow read this value in a variable - say, with something like the following pseudocode:
varval = "inline.dat"(1,1) # get first element of first column in variable
plot "inline.dat" using ($1-varval):2 with impulses linewidth 2
... and with something like this, one wouldn't have to specify this "x offset" value, so to speak, manually in the plot command.
So - to rephrase - is there a way to read the start of x series (the first value of a g