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1.4.1 New syntax

This version of gnuplot introduces command iteration and block-structured if/else/while/do constructs. See `if`, `while`, and `do`. Simple iteration is possible inside `plot` or `set` commands. See iteration. General iteration spanning multiple commands is possible using a block construct as shown below. For a related new feature, see the `summation` expression type. Here is an example using several of these new syntax features:

           set multiplot layout 2,2
           fourier(k, x) = sin(3./2*k)/k * 2./3*cos(k*x)
           do for [power = 0:3] {
               TERMS = 10**power
               set title sprintf("%g term Fourier series",TERMS)
               plot 0.5 + sum [k=1:TERMS] fourier(k,x) notitle
           }
           unset multiplot
     

It is now possible to select a column of data from a data file by matching a label in the first row of the file. See columnhead. For example

           plot for [crop in "Oats Peas Beans"] 'data' using "Year":crop