split — Split text values into substrings using delimiter rules with MATLAB-compatible container behavior.

split(text) breaks text into substrings separated by delimiters across string, char, and cell-text inputs. It follows MATLAB-compatible default-delimiter and output-container behavior, including whitespace splitting when no delimiter is provided.

Syntax

newStr = split(str)
newStr = split(str, delimiter)
newStr = split(str, delimiter, Name, Value, ...)
newStr = split(str, Name, Value, ...)

Inputs

Returns

Errors

How split works

• The default delimiter is whitespace (isspace), and consecutive whitespace is treated as a single separator (equivalent to 'CollapseDelimiters', true).
• When you supply explicit delimiters, they can be a string scalar, string array, character array (rows), or a cell array of character vectors. Delimiters are matched left to right and the longest delimiter wins when several candidates match at the same position.
• 'CollapseDelimiters' controls whether consecutive delimiters generate empty substrings. The default is false when you specify explicit delimiters and true when you rely on the whitespace default.
• 'IncludeDelimiters' inserts the matched delimiters as separate elements in the output string array.
• Outputs are string arrays. For scalar inputs, the result is a row vector. For string/character arrays, the first dimension matches the number of rows in the input and additional columns are appended to accommodate the longest token list. Missing values are padded with <missing>.
• Missing string scalars propagate unchanged.

Does RunMat run split on the GPU?

split executes on the CPU. When the input or delimiter arguments reside on the GPU, RunMat gathers them to host memory before performing the split so the results match MATLAB exactly. Providers do not need to implement custom kernels for this builtin today.

GPU memory and residency

String manipulation currently runs on the host. If text data lives on the GPU (for example after a gathered computation), split automatically fetches it. You never need to move text explicitly before calling this builtin.

Examples

Split A String On Whitespace

txt = "RunMat Accelerate Planner";
pieces = split(txt)

Expected output:

pieces = 1×3 string
    "RunMat"    "Accelerate"    "Planner"

Split A String Using A Custom Delimiter

csv = "alpha,beta,gamma";
tokens = split(csv, ",")

Expected output:

tokens = 1×3 string
    "alpha"    "beta"    "gamma"

Include Delimiters In The Output

expr = "A+B-C";
segments = split(expr, ["+", "-"], "IncludeDelimiters", true)

Expected output:

segments = 1×5 string
    "A"    "+"    "B"    "-"    "C"

Preserve Empty Segments When CollapseDelimiters Is False

values = "one,,three,";
parts = split(values, ",", "CollapseDelimiters", false)

Expected output:

parts = 1×4 string
    "one"    ""    "three"    ""

Split Each Row Of A Character Array

rows = char("GPU Accelerate", "VM Interpreter");
result = split(rows)

Expected output:

result = 2×2 string
    "GPU"          "Accelerate"
    "VM"           "Interpreter"

Split Elements Of A Cell Array

C = {'RunMat Snapshot'; "Fusion Planner"};
out = split(C, " ")

Expected output:

out = 2×2 string
    "RunMat"    "Snapshot"
    "Fusion"    "Planner"

Handle Missing String Inputs

names = ["RunMat", "<missing>", "Accelerate Engine"];
split_names = split(names)

Expected output:

split_names = 3×2 string
    "RunMat"        "<missing>"
    "<missing>"     "<missing>"
    "Accelerate"    "Engine"

Using split with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how split changes the result.

FAQ

Related Strings functions

Open-source implementation

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

• View the source for split in Rust on GitHub
• Learn how the RunMat runtime works
• Found a bug? Open an issue with a minimal reproduction.

About RunMat

RunMat is an open-source runtime that executes MATLAB-syntax code blazing on any GPU. It is licensed under the Apache 2.0 license.

• RunMat automatically optimizes your math for GPU execution on Apple, Nvidia, and AMD hardware. No code changes needed. Simulations that took hours now take minutes.
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