I'm new to SO and Matlab so please excuse any transgressions. I'm trying to convert a seemingly simple array of timestamp strings to an equivalent array of seconds.

I wrote a this function:

% Function to calculate seconds from a timestamp in the following format:

% ddd hh:mm:ss.SSSS (example: 123 12:59:00.9999)

function a = TimestampToS(stamp)

% Uses the "named tokens" facility of MATLAB's "regexp" function.

expr = ['(?\d+)' ... % ddd

' ' ... % Space " " separator

'(?\d+)' ... % hh

':' ... % Colon ":" separator

'(?\d+)' ... % mm

':' ... % Colon ":" separator

'(?\d+)' ... % ss

'.' ... % Dot "." separator

'(?\d+)']; % SSSS

parsedStamp = regexp(stamp, expr, 'names');

a = (str2double(parsedStamp.ddd) * 86400) + ...

(str2double(parsedStamp.hh) * 3600) + ...

(str2double(parsedStamp.mm) * 60) + ...

(str2double(parsedStamp.ss)) + ...

(str2double(parsedStamp.SSSS) * 0.0001);

It works great for an individual string:

>> TimestamptoS('123 12:59:00.9999')

ans =

1.067394099990000e+007

But if I try to use a cell array I get:

Attempt to reference field of non-structure array.

How can I get an array of seconds? I have tried all kinds of conversions of the input data and "parsedStamp" but nothing works. I don't understand Matlab or its matrix notation well enough. Any help gratefully received!

PS This is not a regexp question, no replies about regexp please!