RegEx not working in MATLAB - regex

Question

I have not done any RegEx work in MATLAB, I do not think this is an environment issue but I am not sure. Here is my task:
Download NASDQ stock data from ftp://ftp.nasdaqtrader.com/symboldirectory/nasdaqtraded.txt
Extract all stock symbols using a RegEx
Here is the RegEx that I created: ^[A-Z]\|([A-Z]+)\|.+\|[A-Z]\|[A-Z]\|[A-Z]\|\d\d\d\|[A-Z]\|[A-Z]\|.*\|[A-Z]+$
This expression works on some, but not all lines in this file. For example, it works perfectly for this line:
- Y|AAPL|Apple Inc. - Common Stock|Q|Q|N|100|N|N||AAPL
However it does not match anything from this line:
- Y|A|Agilent Technologies, Inc. Common Stock|N| |N|100|N||A|A
- Y|AAMC|Altisource Asset Management Corp Com|A| |N|100|N||AAMC|AAMC
Help please...thanks!

Answer 1

Your file seems to be a set of columns delimited with |, with first line being column names.
Here is a solution to create directly structure array whose field names are obtained from column names:
function [structArray] = ReadNasdaqTraded(filename)
%[
% For debug
if (nargin < 1), filename = 'nasdaqtraded.txt'; end
% Read full file content
text = fileread(filename);
% Split on newline
text = strsplit(strtrim(text), '\n');
header = text{1}; % Keep header
content = text(2:(end-1)); % Keep content
footer = text{end}; %#ok - We don't care about last line (file creation date)
% Build suitable field names
fieldNames = strsplit(header, '|');
fieldNames = strtrim(fieldNames); % Remove any
fieldNames = strrep(fieldNames, ' ', ''); % spaces (TODO: OR special characters)
% Reformat content into cell matrix
count = length(content);
columnCount = length(fieldNames);
cellArray = cell(count, columnCount);
for ri = 1:count,
cellArray(ri, :) = strsplit(content{ri}, '|', 'CollapseDelimiters', false); % Carefull not to collapse empty delimiters
end
% Create structure array from cell content
structArray = cell2struct(cellArray, fieldNames, 2);
%]
It returns some result like this:
>> ReadNasdaqTraded('nasdaqtraded.txt')
ans =
8188x1 struct array with fields:
NasdaqTraded
Symbol
SecurityName
ListingExchange
MarketCategory
ETF
RoundLotSize
TestIssue
FinancialStatus
CQSSymbol
NASDAQSymbol
Easy to use then for whatever extra processing you need ...