Map range: Difference between revisions

=={{header|Frink}}==

Frink can exactly map to rational numbers so the mapping is round-trippable.

<lang frink>mapRange[s, a1, a2, b1, b2] := b1 + (s-a1)(b2-b1)/(a2-a1)

for a = 0 to 10

println["$a\t" + mapRange[a, 0, 10, -1, 0]]</lang>

{{out}}

<pre>

0 -1

1 -9/10 (exactly -0.9)

2 -4/5 (exactly -0.8)

3 -7/10 (exactly -0.7)

4 -3/5 (exactly -0.6)

5 -1/2 (exactly -0.5)

6 -2/5 (exactly -0.4)

7 -3/10 (exactly -0.3)

8 -1/5 (exactly -0.2)

9 -1/10 (exactly -0.1)

10 0

</pre>