csv2cell

Parse CSV files from Excel, mixed data types, to cell array.

% CSV2CELL - parses a Windows CSV file into an NxM cell array, where N is
% the number of lines in the CSV text and M is the number of fields in the
% longest line of the CSV file. Lines are delimited by carriage returns
% and/or newlines.
%
% A Windows CSV file format allows for commas (,) and double quotes (") to
% be contained within fields of the CSV file. Regular fields are just text
% separated by commas (e.g. foo,bar,hello world). Fields containing commas
% or double quotes are surrounded by double quotes (e.g.
% foo,bar,"item1,item2,item3",hello world). In the previous example,
% "item1,item2,item3" is one field in the CSV text. For double quotes to be
% represented, they are written in pairs in the file, and contained within
% a quoted field, (e.g. foo,"this field contains ""quotes""",bar). Spaces
% within fields (even leading and trailing) are preserved.
%
% All fields from the CSV file are returned as strings. If the CSV text
% contains lines with different numbers of fields, then the "missing"
% fields with appear as empty arrays, [], in the returned data. You can
% easily convert the data you expect to be numeric using str2num() and
% num2cell().
%
% Examples:
% >> csv2cell('foo.csv','fromfile') % loads and parses entire file
% >> csv2cell(',,,') % returns cell array {'','','',''}
% >> csv2cell(',,,','text') % same as above, declaring text input
% >> csv2cell(sprintf('%s\r\n%s',...
% '"Ten Thousand",10000,,"10,000","""It''s ""10 Grand"", baby",10k',...
% ',foo,bar,soo'))
% ans =
% 'Ten Thousand' '10000' '' '10,000' [1x22 char] '10k'
% '' 'foo' 'bar' 'soo' [] []
% >> % note the two empty [] cells, because the second line has two fewer
% >> % fields than the first. The empty field '' at the beginning of the
% >> % second line is due to the leading comma on that line, which is
% >> % correct behavior. A trailing comma will do the same to the end of a
% >> % line.
%
% Limitations/Exceptions:
% * This code is untested on large files. It may take a long time due to
% variables growing inside loops (yes, poor practice, but easy coding).
% * This code has been minimally tested to work with a variety of weird
% Excel files that I have.
% * Behavior with improperly formatted CSV files is untested.
% * Technically, CSV files from Excel always separate lines with the pair
% of characters \r\n. This parser will also separate lines that have only
% \r or \n as line terminators.
% * Line separation is the first operation. I don't think the Excel CSV
% format has any allowance for newlines or carriage returns within
% fields. If it does, then this parser does not support it and would not
% return bad output.