erase — Remove substring occurrences from text inputs in MATLAB and RunMat.

erase(text, pattern) removes every occurrence of pattern from text. Supported text/pattern forms and expansion behavior match MATLAB semantics.

Syntax

newStr = erase(str, pattern)

Inputs

Returns

Errors

How erase works

• String inputs stay as strings. Missing string scalars (<missing>) propagate unchanged.
• String arrays preserve their size and orientation. Each element has every supplied pattern removed.
• Character arrays are processed row by row. Rows shrink as characters are removed and are padded with spaces so the result remains a rectangular char array.
• Cell arrays must contain string scalars or character vectors. The result is a cell array with the same shape whose elements reflect the removed substrings.
• The pattern input can be a string scalar, string array, character array, or cell array of character vectors/string scalars. Provide either a scalar pattern or a list; an empty list leaves text unchanged.
• Pattern values are treated literally—no regular expressions are used. Use replace or the regex builtins for pattern-based removal.

Does RunMat run erase on the GPU?

erase executes on the CPU. When any argument is GPU-resident, RunMat gathers it to host memory before removing substrings. Outputs are returned on the host as well. Providers do not need to implement device kernels for this builtin, and the fusion planner treats it as a sink to avoid keeping text on the GPU.

GPU memory and residency

No. erase automatically gathers GPU inputs and produces host results. You never need to move text to or from the GPU manually for this builtin, and gpuArray inputs are handled transparently.

Examples

Remove a single word from a string scalar

txt = "RunMat accelerates MATLAB code";
clean = erase(txt, "accelerates ")

Expected output:

clean = "RunMat MATLAB code"

Remove multiple substrings from each element of a string array

labels = ["GPU pipeline"; "CPU pipeline"];
result = erase(labels, ["GPU ", "CPU "])

Expected output:

result = 2×1 string
    "pipeline"
    "pipeline"

Erase characters from a character array while preserving padding

chars = char("workspace", "snapshots");
trimmed = erase(chars, "s")

Expected output:

trimmed =

  2×8 char array

    'workpace'
    'naphot '

Remove substrings from a cell array of text

C = {'Kernel Planner', "GPU Fusion"};
out = erase(C, ["Kernel ", "GPU "])

Expected output:

out = 1×2 cell array
    {'Planner'}    {"Fusion"}

Provide an empty pattern list to leave the text unchanged

data = ["alpha", "beta"];
unchanged = erase(data, string.empty)

Expected output:

unchanged = 1×2 string
    "alpha"    "beta"

Remove delimiters before splitting text

path = "runmat/bin:runmat/lib";
clean = erase(path, ":")
parts = split(clean, "runmat/")

Expected output:

clean = "runmat/binrunmat/lib"
parts = 1×3 string
    ""    "bin"    "lib"

Using erase with coding agents

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

FAQ

Related Strings functions

Open-source implementation

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

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

About RunMat

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