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48 CHAPTER 6. PROGRAMMING FACILITIESeng 3 append geng 3 10 numeng 3 appendsci 0 10 expdigits 2 expsignpifracfix 20.00 g 500 g 1.00 kg 1.50 kg 2.00 kg1.00 10 -6 100 10 -6 10.0 10 -3 1.00 10 0 100 10 0 10.0 10 3 1.00 10 61.00 100 10.0 m 1.00 100 10.0 k 1.00 M10 -06 10 -04 10 -02 10 +00 10 +02 10 +04 10 +060 /2 3 /2 2-1 -3/4 -1/2 -1/4 0 1/4 1/2 3/4 1-1.00 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 1.00Figure 6.1: Examples of number formatting options.gle -o beans.eps graph.gle "Beans" "beans.csv"gle -o peas.eps graph.gle "Peas" "peas.csv"This will create two graphs: “beans.eps” and “peas.eps”. The arg() functions can be used at allplaces in the script where an expression is expected. They can even be used in place of GLEcommands in a graph block by means of the \expr() function. For example,data "file.csv"d\expr{arg(1)} line color redin the graph block will allow one to draw different datasets from a single file on multiple graphs.To do so, run:gle -o d1.eps graph.gle 1gle -o d2.eps graph.gle 2dataxvalue(ds,i), datayvalue(ds,i), ndata(ds)These functions can be used to retrieve the data values from a given dataset. They only work afterdata has been loaded by means of a graph block (Ch. 4).A dataset is specified with a dataset identifier ds (a string of the form “di”, with i an integer).The function ‘ndata’ returns the number of points in the dataset, and the functions ‘dataxvalue’ and‘datayvalue’ return the x and y values of point i, where i ranges from 1 to ndata(ds).The following example shows how these functions can be used to compute the maximum of a dataset:sub dmaxy ds$local crmax = datayvalue(ds$,1)for i = 2 to ndata(ds$)crmax = max(crmax, datayvalue(ds$,i))next ireturn crmaxend subThis subroutine together with other subroutines for computing the minimum, mean, area, etc. ofa dataset are defined in the include file ‘graphutil.gle’, which is distributed together with GLE.format$(exp,format)Returns a string representation of exp formatted as specified in format.Basic formats:• append s: appends the string s after the formatted number. This can be used to add a unit.