Loop structure inside gnuplot

gnuplot

Is there any way to iteratively retrieve data from multiple files and plot them on the same graph in gnuplot. Suppose I have files like data1.txt, data2.txt……data1000.txt; each having the same number of columns. Now I could write something like-

plot "data1.txt" using 1:2 title "Flow 1", \
     "data2.txt" using 1:2 title "Flow 2", \
      .
      .
      .
     "data1000.txt"  using 1:2 title "Flow 6"

But this would be really inconvenient. I was wondering whether there is a way to loop through the plot part in gnuplot.

Best Answer

There sure is (in gnuplot 4.4+):

plot for [i=1:1000] 'data'.i.'.txt' using 1:2 title 'Flow '.i

The variable i can be interpreted as a variable or a string, so you could do something like

plot for [i=1:1000] 'data'.i.'.txt' using 1:($2+i) title 'Flow '.i

if you want to have lines offset from each other.

Type help iteration at the gnuplot command line for more info.

Also be sure to see @DarioP's answer about the do for syntax; that gives you something closer to a traditional for loop.

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Gnuplot draw two plots on the same graph with single column data

You could get two plots on the same graph in one plot command with two datafile arguments, separated by a comma. For instance

  plot [-1:5] 'data1.txt' with points, 'data2.txt' with points

would get you something like this:

enter image description here

Gnuplot: how to put two figures side by side

Try something like:

set terminal postscript eps color enhanced size 10,5
set output 'figure.eps';

set multiplot layout 1, 2 ;
set title "Figure 1";
plot  "data1.txt" 
set title "Figure 1";
plot  "data2.txt" 
unset multiplot

When you set the size on the terminal specification line, that determines the actual size of the plot canvas (in inches in this case). When you use set size on a separate line, that sets the size of the plot in relative units of the canvas size. This is different in older versions of gnuplot. For perhaps a better explanation, try help set size in gnuplot.

Best Answer

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Gnuplot draw two plots on the same graph with single column data

Gnuplot: how to put two figures side by side

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