randsample — Randomly sample from an integer range or population vector.
randsample(n,k) samples from integers 1:n. randsample(population,k) samples from a population vector. Replacement and weights are supported with randsample(...,replacement,w).
Syntax
y = randsample(n, k)
y = randsample(population, k)
y = randsample(___, replacement, w)Inputs
| Name | Type | Required | Default | Description |
|---|---|---|---|---|
n | Any | Yes | — | Population size or upper discrete uniform bound. |
k | Any | Yes | — | Number of samples. |
data | Any | Yes | — | Population to sample from. |
options | Any | Variadic | — | Dimension, replacement, and weights options. |
Returns
| Name | Type | Description |
|---|---|---|
y | Any | Random sample. |
Errors
| Identifier | When | Message |
|---|---|---|
RunMat:randsample:InvalidArgument | Inputs, dimensions, replacement flags, or weights are malformed. | sampling: invalid argument |
RunMat:randsample:Internal | Internal conversion or allocation fails. | sampling: internal error |
How randsample works
- Samples without replacement by default.
- When the first argument is a numeric scalar, it is treated as the upper limit
n. - Population vectors preserve their row or column orientation.
- Weights are supported for sampling with replacement, matching MATLAB's documented restriction.
- The documented numeric range, population, count, and weight classes are single and double, while replacement is logical. Typed-integer range limits, populations, counts, replacement flags, and weights are five independently gated RunMat-mode extensions.
- Typed-integer populations preserve exact native class, orientation, and supported owner residency; weights cross a checked binary64 probability boundary, while range limits, counts, and replacement flags remain structural.
- Numeric, logical, string, and char population vectors are supported.
Examples
Sample unique integers
y = randsample(20, 10)Sample with replacement and weights
y = randsample(population, 5, true, weights)Using randsample with coding agents
Open a RunMat example with live inputs, then ask the agent to explain how randsample changes the result.
Run a small randsample example, explain the result, then change one input and compare the output.
FAQ
How is randsample different from datasample?⌄
randsample(n,k) is specialized for integer ranges and population vectors. Use datasample to sample along dimensions of arrays.
Related Stats functions
Random
binornd · bootstrp · datasample · dividerand · exprnd · gamrnd · lhsdesign · mvnrnd · normrnd · random · rng · trnd · unidrnd · unifrnd · wblrnd
Ml
bayesopt · classify · confusionmat · crossvalind · cvpartition · fitclinear · fitctree · fitlm · kmeans · knnsearch · lasso · lassoglm · linkage · lscov · mnrfit · optimizableVariable · pdist · pdist2 · perfcurve · predict · regress · ridge · squareform · test · training · tsne
Summary
binocdf · boxplot · cdf · cdfplot · chi2cdf · corr · corrcoef · corrcov · cov · cov2corr · dummyvar · ecdf · filloutliers · fitdist · geomean · grpstats · harmmean · icdf · isoutlier · kstest · kurtosis · lsline · mad · mode · nanmax · normalize · normcdf · norminv · normpdf · onehotdecode · onehotencode · pdf · prctile · quantile · refline · rmse · skewness · tabulate · tcdf · tiedrank · tinv · tpdf · ttest2 · wblinv
Hist
Open-source implementation
Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how randsample is executed, line by line, in Rust.
- View the source for randsample in Rust on GitHub
- Learn how the RunMat runtime works
- Found a bug? Open an issue with a minimal reproduction.
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