liststat.tcl

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/*  liststat.tcl --*/
/* */
/*     Set of operations on lists, meant for the statistics package*/
/* */
/*  version 0.1: initial implementation, january 2003*/

namespace ::math::statistics {}

/*  filter --*/
/*     Filter a list based on whether an expression is true for*/
/*     an element or not*/
/* */
/*  Arguments:*/
/*     varname        Name of the variable that represents the data in the*/
/*                    expression*/
/*     data           List to be filtered*/
/*     expression     (Logical) expression that is to be evaluated*/
/* */
/*  Result:*/
/*     List of those elements for which the expression is true*/
/*  TODO:*/
/*     Substitute local variables in caller*/
/* */
ret  ::math::statistics::filter ( type varname , type data , type expression ) {
   upvar $varname _x_
   set result {}
   set _x_ \$_x_
   set expression [uplevel subst -nocommands [list $expression]]
   foreach _x_ $data {
      # FRINK: nocheck
      if $expression {

         lappend result $_x_
      }
   }
   return $result
}

/*  map --*/
/*     Map the elements of a list according to an expression*/
/* */
/*  Arguments:*/
/*     varname        Name of the variable that represents the data in the*/
/*                    expression*/
/*     data           List whose elements must be transformed (mapped)*/
/*     expression     Expression that is evaluated with $varname an*/
/*                    element in the list*/
/* */
/*  Result:*/
/*     List of transformed elements*/
/* */
ret  ::math::statistics::map ( type varname , type data , type expression ) {
   upvar $varname _x_
   set result {}
   set _x_ \$_x_
   set expression [uplevel subst -nocommands [list $expression]]
   foreach _x_ $data {
      # FRINK: nocheck
      lappend result [expr $expression]
   }
   return $result
}

/*  samplescount --*/
/*     Count the elements in each sublist and return a list of counts*/
/* */
/*  Arguments:*/
/*     varname        Name of the variable that represents the data in the*/
/*                    expression*/
/*     list           List of lists*/
/*     expression     Expression in that is evaluated with $varname an*/
/*                    element in the sublist (defaults to "true")*/
/* */
/*  Result:*/
/*     List of transformed elements*/
/* */
ret  ::math::statistics::samplescount ( type varname , type list , optional expression =1 ) {
   upvar $varname _x_
   set result {}
   set _x_ \$_x_
   set expression [uplevel subst -nocommands [list $expression]]
   foreach data $list {
      set number 0
      foreach _x_ $data {
         # FRINK: nocheck
         if $expression {
            incr number
         }
      }
      lappend result $number
   }
   return $result
}

/*  End of list procedures*/