feelgood

Ok, lets say I have a set of number and each one starts out as equal probabilty of appearing (20%).
{0, 1, 2, 3, 4}
{.2, .2, .2, .2, .2}

Let's say that I want to change the probability of #2 appearing to 50%. That would mean that the probability of other 4 numbers {0, 1, 3, 4} will adjust accordingly to appear 12.5% of the times.
{0, 1, 2, 3, 4}
{.125, .125, .5, .125, .125}

It's easy to figure out how to adjust the probability automatically for other number when you're setting the frequency of one particular number for the first time.

Here's the head scratcher for me, once I change the probabilty of one particular number and then change the probabilty of a second number. For example, I want to set the probability of 0 appearing 30% of the time and at the same time, automatically adjust other frequencies accordingly as long the sum is equal to 1.

How would I adjust other number automatically? Is there a formula?

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