function [c, matches] = strsplit(str, aDelim, varargin)

%STRSPLIT  Split string at delimiter

%   C = STRSPLIT(STR) splits the character vector or string scalar STR at

%   whitespace into C.

%

%   C = STRSPLIT(STR, DELIMITER) splits STR at DELIMITER into C. If

%   DELIMITER is a cell array of character vectors, STRSPLIT splits STR

%   along the elements in DELIMITER, in the order in which they appear in

%   the cell array.

%

%   C = STRSPLIT(STR, DELIMITER, PARAM1, VALUE1, ... PARAMN, VALUEN)

%   modifies the way in which STR is split at DELIMITER.

% 

%     Valid parameters are:

%

%     'CollapseDelimiters' - If true (default), consecutive delimiters in

%         STR are treated as one. If false, consecutive delimiters are

%         treated as separate delimiters, resulting in text with no

%         characters between matched delimiters.

%     'DelimiterType' - DelimiterType can have the following values:

%         'Simple' (default) - Except for escape sequences, STRSPLIT treats

%             DELIMITER as a literal.

%         'RegularExpression' - STRSPLIT treats DELIMITER as a regular

%             expression.

%         In both cases, DELIMITER can include the following escape

%         sequences:

%             \\   Backslash             \n   New line

%             \0   Null                  \r   Carriage return

%             \a   Alarm                 \t   Horizontal tab

%             \b   Backspace             \v   Vertical tab

%             \f   Form feed

%

%   [C, MATCHES] = STRSPLIT(...) also returns the cell array of character

%   vectors MATCHES containing the DELIMITERs upon which STR was split.

%   Note that MATCHES always contains one fewer element than C.

%

%   NOTE: STR can be a string array or character vector. DELIMITER can be

%   a string array, character vector, or cell array of character vectors.

%   When STR is a string array, outputs C and MATCHES are string arrays.

%   Otherwise, C and MATCHES are cell arrays of character vectors.

%

%   Examples:

%

%       str = 'The rain in Spain stays mainly in the plain.';

%

%       % Split on all whitespace.

%       strsplit(str)

%       % {'The', 'rain', 'in', 'Spain', 'stays',

%       %  'mainly', 'in', 'the', 'plain.'}

%

%       % Split on 'ain'.

%       strsplit(str, 'ain')

%       % {'The r', ' in Sp', ' stays m', 'ly in the pl', '.'}

%

%       % Split on ' ' and on 'ain' (treating multiple delimiters as one).

%       strsplit(str, {' ', 'ain'})

%       % {'The', 'r', 'in', 'Sp', 'stays',

%       %  'm', 'ly', 'in', 'the', 'pl', '.'}

%

%       % Split on all whitespace and on 'ain', and treat multiple

%       % delimiters separately.

%       strsplit(str, {'\s', 'ain'}, 'CollapseDelimiters', false, ...

%                     'DelimiterType', 'RegularExpression')

%       % {'The', 'r', '', 'in', 'Sp', '', 'stays',

%       %  'm', 'ly', 'in', 'the', 'pl', '.'}

%

%   See also SPLIT, JOIN, STRJOIN, REGEXP, CONTAINS, COUNT, EXTRACTBETWEEN,

%   STRFIND

%   Copyright 2012-2016 The MathWorks, Inc.

% Initialize default values.

collapseDelimiters = true; 

delimiterType = 'Simple'; 

% Check input arguments.

if nargin < 1 

    narginchk(1, Inf);

elseif ~ischar(str) && ~(isstring(str) && isscalar(str)) 

    error(message('MATLAB:strsplit:InvalidStringType'));

end 

if nargin < 2 

    delimiterType = 'RegularExpression'; 

    aDelim = {'\s'}; 

elseif ischar(aDelim)

    aDelim = {aDelim};

elseif isstring(aDelim)

    aDelim(ismissing(aDelim)) = [];

    aDelim = cellstr(aDelim);

elseif ~iscellstr(aDelim)

    error(message('MATLAB:strsplit:InvalidDelimiterType'));

end 

if nargin > 2 

    funcName = mfilename;

    p = inputParser;

    p.FunctionName = funcName;

    p.addParameter('CollapseDelimiters', collapseDelimiters);

    p.addParameter('DelimiterType', delimiterType);

    p.parse(varargin{:});

    collapseDelimiters = verifyScalarLogical(p.Results.CollapseDelimiters, ...

        funcName, 'CollapseDelimiters');

    delimiterType = validatestring(p.Results.DelimiterType, ...

        {'RegularExpression', 'Simple'}, funcName, 'DelimiterType');

end 

% Handle DelimiterType.

if strcmp(delimiterType, 'Simple') 

    % Handle escape sequences and translate.

    aDelim = strescape(aDelim);

    aDelim = regexptranslate('escape', aDelim);

else 

    % Check delimiter for regexp warnings.

    regexp('', aDelim, 'warnings'); 

end 

% Handle multiple delimiters.

aDelim = strjoin(aDelim, '|'); 

% Handle CollapseDelimiters.

if collapseDelimiters 

    aDelim = ['(?:', aDelim, ')+']; 

end 

% Split.

[c, matches] = regexp(str, aDelim, 'split', 'match'); 

end