简单的数学问题

Question

I have a dataset containing n values between 0 and m.

Now i want to map this values in the range between min and max. But how do I do that? If i have in every object this method:

public double getValue(int min, int max) {
   // return value between min and max;
}

This want work I think?

Answer 1

尝试：

return min + (max - min) * (val / m);

Answer 2

If you're talking about mapping the range 0..m to min..max , surely that's just a matter of:

newval = val * (max - min) / m + min

allowing of course for any integer/floating-point gotchas like inadvertent rounding.

The multiplication by (max - min) / m will scale it to the correct range and the addition of min will give it the correct lower offset.

Answer 3

This code is a bit more generic (doesn't take only 0-m range, but any original range):

public double GetValue(int value, 
                       int min, 
                       int max, 
                       int originalMin, 
                       int originalMax) 
{
   return min + (double)(value - originalMin) * (max - min) / (originalMax - originalMin);
}
// in your case originalMin = 0, and originalMax = m