Select a random item from a weighted list

Question

I am trying to write a program to select a random name from the US Census last name list. The list format is

Name           Weight Cumulative line
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Answer 1

I've created a C# library for randomly selected weighted items.

• It implements both the tree-selection and walker alias method algorithms, to give the best performance for all use-cases.
• It is unit-tested and optimized.
• It has LINQ support.
• It's free and open-source, licensed under the MIT license.

Some example code:

IWeightedRandomizer randomizer = new DynamicWeightedRandomizer();
randomizer["Joe"] = 1;
randomizer["Ryan"] = 2;
randomizer["Jason"] = 2;

string name1 = randomizer.RandomWithReplacement();
//name1 has a 20% chance of being "Joe", 40% of "Ryan", 40% of "Jason"

string name2 = randomizer.RandomWithRemoval();
//Same as above, except whichever one was chosen has been removed from the list.