Package org.apache.commons.rng.sampling
Class ListSampler
- java.lang.Object
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- org.apache.commons.rng.sampling.ListSampler
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public final class ListSampler extends Object
- Since:
- 1.0
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static <T> List<T>sample(UniformRandomProvider rng, List<T> collection, int k)Generates a list of sizekwhose entries are selected randomly, without repetition, from the items in the givencollection.static <T> voidshuffle(UniformRandomProvider rng, List<T> list)Shuffles the entries of the given array, using the Fisher-Yates algorithm.static <T> voidshuffle(UniformRandomProvider rng, List<T> list, int start, boolean towardHead)Shuffles the entries of the given array, using the Fisher-Yates algorithm.
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Method Detail
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sample
public static <T> List<T> sample(UniformRandomProvider rng, List<T> collection, int k)
Generates a list of sizekwhose entries are selected randomly, without repetition, from the items in the givencollection.Sampling is without replacement; but if the source collection contains identical objects, the sample may include repeats.
Sampling uses
UniformRandomProvider.nextInt(int).- Type Parameters:
T- Type of the list items.- Parameters:
rng- Generator of uniformly distributed random numbers.collection- List to be sampled from.k- Size of the returned sample.- Returns:
- a shuffled sample from the source collection.
- Throws:
IllegalArgumentException- ifk <= 0ork > collection.size().
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shuffle
public static <T> void shuffle(UniformRandomProvider rng, List<T> list)
Shuffles the entries of the given array, using the Fisher-Yates algorithm.Sampling uses
UniformRandomProvider.nextInt(int).- Type Parameters:
T- Type of the list items.- Parameters:
rng- Random number generator.list- List whose entries will be shuffled (in-place).
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shuffle
public static <T> void shuffle(UniformRandomProvider rng, List<T> list, int start, boolean towardHead)
Shuffles the entries of the given array, using the Fisher-Yates algorithm.The
startandposparameters select which part of the array is randomized and which is left untouched.Sampling uses
UniformRandomProvider.nextInt(int).- Type Parameters:
T- Type of the list items.- Parameters:
rng- Random number generator.list- List whose entries will be shuffled (in-place).start- Index at which shuffling begins.towardHead- Shuffling is performed for index positions betweenstartand either the end (iffalse) or the beginning (iftrue) of the array.
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