function s = rmfield(s,field)

%RMFIELD Remove fields from a structure array.

%   S = RMFIELD(S,FIELD) removes the field specified by FIELD from the 

%   m x n structure array S. For example, S = RMFIELD(S,'a') removes the field

%   'a' from S. The size of input S is preserved.

%

%   S = RMFIELD(S,FIELDS) removes more than one field at a time when FIELDS

%   is a string, character array or cell array of character vectors. The

%   changed structure is returned. The size of input S is preserved.

%

%   See also SETFIELD, GETFIELD, ISFIELD, FIELDNAMES.

%   Copyright 1984-2017 The MathWorks, Inc.

%--------------------------------------------------------------------------------------------

% handle input arguments

if ~isa(s,'struct') 

    error(message('MATLAB:rmfield:Arg1NotStructArray'));

end

field = convertStringsToChars(field); 

if iscell(field) && isempty(field) 

    % No fields to remove

    return

end

if ~ischar(field) && ~iscellstr(field) 

    error(message('MATLAB:rmfield:FieldnamesNotStrings'));

end

if ischar(field) && ~isrow(field) 

    % converts char matrix to cell-str but leave char vector alone

    field = cellstr(field);

end

% get fieldnames of struct

f = fieldnames(s); 

% Determine which fieldnames to delete.

if ischar(field) || isscalar(field) 

    % shortcut for single field.

    nonexistent = []; 

    toRemove = strcmp(deblank(field),f); 

    if ~any(toRemove) 

        nonexistent = find(~toRemove,1);

    end

elseif numel(f) < 100 && numel(field) < 10

    % faster for small number of fields

    [toRemove,nonexistent] = smallcase(f,field);

else

    % faster for large number of fields.

    [toRemove,nonexistent] = generalcase(f,field);

end

% If any given fields were not found, throw an error

if ~isempty(nonexistent) 

    field = cellstr(field);

    name = field{nonexistent};

    % Make sure the given non-existent field name does not exceed max length

    if length(name) > namelengthmax

        error(message('MATLAB:rmfield:FieldnameTooLong', name));

    else

        error(message('MATLAB:rmfield:InvalidFieldname', name));

    end

end

% convert struct to cell array

c = struct2cell(s); 

% find size of cell array

sz = size(c); 

% adjust size for fields to be removed

sz(1) = sz(1) - nnz(toRemove); 

% rebuild struct

s = cell2struct(reshape(c(~toRemove,:),sz),f(~toRemove)); 

%--------------------------------------------------------------------------------------------

end