strjoin — Join text across each input row using an explicit delimiter.

strjoin joins text across each row of the input using the delimiter you provide. RunMat's current implementation accepts string scalars, string arrays, and character arrays, converts character-array rows into strings, and returns a column string array containing one joined result per input row.

How strjoin works

• strjoin(str, delim) requires an explicit delimiter argument in the current implementation.
• String arrays are joined row-wise across columns, producing one output string per row.
• Character arrays are first interpreted row-by-row and then joined the same way.
• The return type is always a string array.
• Empty inputs with zero rows or zero columns currently return an empty 0x0 string array.
• Cell arrays of character vectors are not currently accepted by this implementation.

How RunMat runs strjoin on the GPU

strjoin performs no provider dispatch. GPU-resident text inputs are gathered before the join is computed on the CPU.

GPU memory and residency

No. strjoin gathers text to host memory and returns a host-side string array.

Examples

Join a row vector of strings with commas

labels = ["alpha" "beta" "gamma"];
out = strjoin(labels, ", ")

Expected output:

out = "alpha, beta, gamma"

Join each row of a string matrix independently

names = ["Ada" "Lovelace"; "Grace" "Hopper"];
out = strjoin(names, " ")

Expected output:

out = 2×1 string
    "Ada Lovelace"
    "Grace Hopper"

Join rows of a character array

chars = ['ab'; 'cd'];
out = strjoin(chars, "-")

Expected output:

out = 2×1 string
    "a-b"
    "c-d"

FAQ

Is the delimiter optional?

Not in the current RunMat implementation. Pass strjoin(str, delim) explicitly.

Does strjoin join by row or by column?

It joins across columns within each row, returning one output string per input row.

Can I pass a cell array of character vectors?

Not currently. This implementation accepts string scalars, string arrays, and character arrays.

Related Strings functions

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how strjoin works, line by line, in Rust.

• View strjoin.rs on GitHub
• Learn how the runtime works
• Found a bug? Open an issue with a minimal reproduction.

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