Map range: Difference between revisions
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10 maps to 0</pre>
=={{header|SparForte}}==
As a structured script.
<syntaxhighlight lang="ada">#!/usr/local/bin/spar
pragma annotate( summary, "mapping" )
@( description, "The task is to write a function/subroutine/... that takes" )
@( description, "two ranges and a real number, and returns the mapping of" )
@( description, "the real number from the first to the second range. Use" )
@( description, "this function to map values from the range [0, 10] to the" )
@( description, "range [-1, 0]." )
@( see_also, "http://rosettacode.org/wiki/Map_range" )
@( author, "Ken O. Burtch" );
pragma license( unrestricted );
pragma restriction( no_external_commands );
procedure mapping is
type first_range is new float;
type second_range is new float;
-- Spar doesn't implement ranges so we'll use constants
first_range_first : constant first_range := 0.0;
first_range_last : constant first_range := 10.0;
second_range_first : constant second_range := -1.0;
second_range_last : constant second_range := 0.0;
function translate (first_range_value : first_range) return second_range is
b1 : constant float := float( second_range_first );
b2 : constant float := float( second_range_last );
a1 : constant float := float( first_range_first );
a2 : constant float := float( first_range_last );
result : float;
begin
result := b1 + (float (first_range_value) - a1) * (b2 - b1) / (a2 - a1);
return second_range(result);
end translate;
function translate_back (second_range_value : second_range) return first_range is
b1 : constant float := float (first_range_first);
b2 : constant float := float (first_range_last);
a1 : constant float := float (second_range_first);
a2 : constant float := float (second_range_last);
result : float;
begin
result := b1 + (float (second_range_value) - a1) * (b2 - b1) / (a2 - a1);
return first_range (result);
end translate_back;
test_value : first_range := first_range_first;
translated_value : second_range;
translated_back_value : first_range;
begin
loop
translated_value := translate( test_value );
translated_back_value := translate_back( translated_value );
? strings.image(test_value) & " maps to: "
& strings.image (translated_value);
? strings.image(translated_value) & " maps back to: "
& strings.image (translated_back_value);
exit when test_value = first_range_last;
test_value := @ + 1.0;
end loop;
end mapping;</syntaxhighlight>
{{out}}
<pre>
$ spar mapping.sp
0.0 maps to: -1.00000000000000E+00
-1.00000000000000E+00 maps back to: 0.00000000000000E+00
1.00000000000000E+00 maps to: -9.00000000000000E-01
-9.00000000000000E-01 maps back to: 1.00000000000000E+00
2.00000000000000E+00 maps to: -8.00000000000000E-01
-8.00000000000000E-01 maps back to: 2.00000000000000E+00
3.00000000000000E+00 maps to: -7.00000000000000E-01
-7.00000000000000E-01 maps back to: 3.00000000000000E+00
4.00000000000000E+00 maps to: -6.00000000000000E-01
-6.00000000000000E-01 maps back to: 4.00000000000000E+00
5.00000000000000E+00 maps to: -5.00000000000000E-01
-5.00000000000000E-01 maps back to: 5.00000000000000E+00
6.00000000000000E+00 maps to: -4.00000000000000E-01
-4.00000000000000E-01 maps back to: 6.00000000000000E+00
7.00000000000000E+00 maps to: -3.00000000000000E-01
-3.00000000000000E-01 maps back to: 7.00000000000000E+00
8.00000000000000E+00 maps to: -2.00000000000000E-01
-2.00000000000000E-01 maps back to: 8.00000000000000E+00
9.00000000000000E+00 maps to: -1.00000000000000E-01
-1.00000000000000E-01 maps back to: 9.00000000000000E+00
1.00000000000000E+01 maps to: 0.00000000000000E+00
0.00000000000000E+00 maps back to: 1.00000000000000E+01</pre>
=={{header|Stata}}==
The following program will map a variable to a new variable. It accepts '''if''' and '''in''' conditions.
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