strsplit — Split a string scalar or character vector into substrings using simple or regular-expression delimiters.

strsplit(str) splits a string scalar or character vector into substrings. RunMat implements the MATLAB-style scalar-text API, including 'CollapseDelimiters', 'DelimiterType', and the optional second output containing the matched delimiters.

How strsplit works

• The first argument must be scalar text: a string scalar or a character vector. Unlike split, strsplit does not accept string arrays, character matrices, or cell arrays of text.
• When you omit the delimiter, strsplit splits on MATLAB's default whitespace set (' ', \f, \n, \r, \t, \v) and collapses consecutive delimiters.
• Explicit delimiters default to 'CollapseDelimiters', true, so adjacent delimiters are grouped unless you opt out.
• Set 'DelimiterType', 'RegularExpression' to interpret delimiters as regex patterns. In 'Simple' mode, delimiters are matched literally and special regex characters are escaped.
• String input returns a row string array. Character-vector input returns a row cell array of text elements.

Examples

Split A Character Vector On Whitespace

txt = 'The rain in Spain.';
parts = strsplit(txt)

Expected output:

parts = 1x4 cell
    {'The'}    {'rain'}    {'in'}    {'Spain.'}

Split Using A Literal Delimiter

csv = "alpha,beta,gamma";
parts = strsplit(csv, ",")

Expected output:

parts = 1x3 string
    "alpha"    "beta"    "gamma"

Return The Matched Delimiters

[parts, matches] = strsplit("a,,b,", ",")

Expected output:

parts = 1x3 string
    "a"    "b"    ""

matches = 1x2 string
    ",,"    ","

Use A Regular Expression Delimiter

[parts, matches] = strsplit("1.21m/s 1.985 m/s", "\s*m/s\s*", "DelimiterType", "RegularExpression")

Expected output:

parts = 1x3 string
    "1.21"    "1.985"    ""

matches = 1x2 string
    "m/s "    " m/s"

Preserve Empty Fields

parts = strsplit("a,,b", ",", "CollapseDelimiters", false)

Expected output:

parts = 1x3 string
    "a"    ""    "b"

FAQ

How is strsplit different from split?

strsplit is the scalar-text API that mirrors MATLAB's older function shape, including optional matches output and regex delimiter mode. split is the vectorized string-array builtin.

What does the second output contain?

The optional matches output returns the delimiter text that produced each split. When delimiters are collapsed, adjacent delimiter runs are grouped into the matched text.

Can strsplit use regular expressions?

Yes. Pass 'DelimiterType', 'RegularExpression' and provide delimiter patterns as regex fragments.

Does strsplit accept string arrays?

No. RunMat currently restricts strsplit to scalar text, matching MATLAB's documented scalar-input API.

Related Strings functions

Open-source implementation

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

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

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