DATASAMPLE Randomly sample from data, with or without replacement.
Y = DATASAMPLE(DATA,K) returns K observations sampled uniformly at random,
with replacement, from the data in DATA. If DATA is a vector, then Y is a
vector containing K elements selected from DATA. If DATA is a matrix, then
Y is a matrix containing K rows selected from DATA. If DATA is an N-D
array, DATASAMPLE samples along its first non-singleton dimension. DATA
may be a dataset array or table. Because the sample is taken with replacement, the
observations that DATASAMPLE selects from DATA may be repeated in Y.
Y = DATASAMPLE(DATA,K,DIM) returns a sample taken along dimension DIM of
DATA. For example, if DATA is a matrix and DIM is 2, Y contains a
selection of DATA's columns. If DATA is a dataset array or table and DIM is 2, Y
contains a selection of DATA's variables. Use DIM to ensure sampling
along a specific dimension regardless of whether DATA is a vector, matrix
or N-dimensional array.
Y = DATASAMPLE(DATA,K, 'PARAM1',val1, 'PARAM2',val2, ...) or Y =
DATASAMPLE(DATA,K,DIM, 'PARAM1',val1, 'PARAM2',val2, ...) specifies
optional parameter name/value pairs to control how DATASAMPLE creates the
sample. Parameters are:
'Replace' - select the sample with replacement if REPLACE is true (the
default), or without replacement if REPLACE is false. When
sampling without replacement, the observations that
DATASAMPLE selects from DATA are unique.
'Weights' - create a weighted sample using the positive weights in
the vector W.
[Y,I] = DATASAMPLE(...) returns an index vector indicating which values
were sampled from DATA. For example, Y = DATA(I) if DATA is a vector,
Y = DATA(I,:) if DATA is a matrix, etc.
DATASAMPLE uses RANDPERM and RANDI to generate random values and therefore
changes the state of MATLAB's global random number generator. Control
that generator using RNG.
Y = DATASAMPLE(S,...) uses the random number stream S for random number
generation.
Examples:
Draw five unique values from the integers 1:10.
y = datasample(1:10,5,'Replace',false)
Generate a random sequence of the characters ACGT, with replacement,
according to specified probabilities.
seq = datasample('ACGT',48,'Weights',[0.15 0.35 0.35 0.15])
Select a random subset of columns from a data matrix.
X = randn(10,1000);
Y = datasample(X,5,2,'Replace',false)
Resample observations from a dataset array to create a bootstrap
replicate dataset.
load hospital
y = datasample(hospital,size(hospital,1))
Use the second output to sample "in parallel" from two data vectors.
x1 = randn(100,1);
x2 = randn(100,1);
[y1,i] = datasample(x1,10)
y2 = x2(i)
See also RAND, RANDI, RANDPERM, RNG.
Documentation for datasample
doc datasample
Other uses of datasample
tall/datasample
