All points y value undefined! in gnuplot

Question

I'm getting this error:

line 0:all points y value undefined!

My code for gnuplot is:

set terminal png 8;
set output "skript01_31/image10.png"; 
set timefmt x "%Y-%m-%d %H:%M:%S";
set xdata time; 
set format x "%H:%M"; 
set xlabel "Cas"; 
set ylabel "Hodnota"; 
set yrange [:]; 
set xrange ["2009-05-11 07:30:00":"2009-06-11 00:34:00"]; 
set title "skript01"; 
set grid;
plot 'skript01_31/gnuplot_file' using 1:3 with points pt 7 ps 1 title "./skript01.sh";

My data file:

[2009-05-11 07:30:00] 0
[2009-05-11 07:31:00] 0.00999983333416666468
[2009-05-11 07:32:00] 0.01999866669333307936
[2009-05-11 07:33:00] 0.02999550020249566076
[2009-05-11 07:34:00] 0.03998933418663415945
[2009-06-11 00:34:00] 0.05

What I'm doing wrong?

Thanks for answer.

Answer 1

For the time format, this should be set timefmt x "[%Y-%m-%d %H:%M:%S]";, with the addition of the square brackets to match the time format used in the data file. Additionally the xrange variable should also acquire additional square brackets to match: set xrange ["[2009-05-11 07:30:00]":"[2009-06-11 00:34:00]"];