Re: Normalizing a range of numbers to a percentage

my $x = (($tap - $min) * ($new_max - $new_min) / ($max - $min)) + $new
+_min;
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In your case $new_min was zero, so your numbers are good.

I think of it this way:

($tap - $min)  / ($max - $min)
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is the ratio on the old scale, then multiply by the new scale and add the new offset.

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Re^2: Normalizing a range of numbers to a percentage by stevieb (Canon) on Mar 07, 2019 at 23:19 UTC
Thanks tybalt89! I did happen to simplify this down a bit because of the zero aspect, but for completeness purposes, may I bug you to add in a couple of examples as to where my OP code wouldn't work? Say if `$new_min` was `5` for example?	[reply] [d/l] [select]
Re^3: Normalizing a range of numbers to a percentage by pryrt (Abbot) on Mar 07, 2019 at 23:23 UTC
With `$new_min = 5`, it would give a range of 0..95 rather than 5..100 if you don't include the offset. With -100 to +100 as the new min/max, it would give 0..200 rather than -100 to +100.	[reply] [d/l]
Re^4: Normalizing a range of numbers to a percentage by stevieb (Canon) on Mar 07, 2019 at 23:30 UTC
"With $new_min = 5, it would give a range of 0..95 rather than 5..100 if you don't include the offset." So the following is what is meant here? `my $x = (($tap - $min) * ($new_max - $new_min + 5) / ($max - $min)); # ^^^` [download]	[reply] [d/l]
Re^5: Normalizing a range of numbers to a percentage by tybalt89 (Monsignor) on Mar 07, 2019 at 23:36 UTC
Re^6: Normalizing a range of numbers to a percentage by pryrt (Abbot) on Mar 08, 2019 at 00:41 UTC
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Re^2: Normalizing a range of numbers to a percentage by pryrt (Abbot) on Mar 07, 2019 at 23:16 UTC
ugh, can't believe I missed that. I do that type of calculation so often, I should have noticed :-(	[reply]
Re^3: Normalizing a range of numbers to a percentage by tybalt89 (Monsignor) on Mar 07, 2019 at 23:41 UTC
I do it so often, I finally wrote a simultaneous equation solver (with Math::BigRat) so I just plug in end points and it gives me the multiplier and constant offset :)	[reply]