Does MATLAB require a 2nd REGEXP to match data values obtained from a previous REGEXP?

I've got a set of commands that look like this:

str = 'Part ID: 1 or Part ID: 2 or Part ID: 5 or Part ID: 10';

exp = '*?Part ID:\s+(\d+)';

tokens = regexp(str, exp, 'tokens');

Part_data = reshape(str2double([tokens{:}]), 1, []).'

The objective of the code is to match only Part ID values 2 and 5. MATLAB is easily extracting all 4 part IDs with the commands above. However, I can't get MATLAB to read ONLY values 2 and 5.

I've been seearching Mathworks and using the MATLAB documentation in hopes of answering the following question: Does MATLAB require a 2nd REGEXP to match data values obtained from a previous REGEXP? Or am I making this harder than it is?

[Ken Atwell]

What is it that makes values 2 and 5 different/special ("keepers") from 1 and 10 ("non-keepers")?

[Brad]

Ken, These values are tied to other parameters that require additional processing.

Answer 1

[Walter Roberson]

exp = 'Part ID:\s+([25])\W';

The expression will match as many times as needed

[Brad]

DOH! I forgot the parentheses around the brackets. Thanks Walter.

Answer 2

[James Kristoff]

The quick solution to the objected you stated is to use a more specific regular expression, i.e. if you only want the values 2 and 5:

exp = '*?Part ID:\s+([2|5])';

The real question is:

• what is the actual motivation behind your question?

Meaning, if you just always want to get 2 and 5, then why not have a static vector of 2 and 5.

• What makes 2 and 5 special/different from 1 and 10?

It is that difference or uniqueness that you should use to isolate the values you want in a more generic algorithm.

[Walter Roberson]

[2|5] means "2" or "|" or "5", not "2" or "5". [25] already means "2" or "5"

[James Kristoff]

Also, a cleaner way of creating a vector of doubles from a cell array is to use the cellfun command, e.g.

Part_data = cellfun(@(str)str2double(str), tokens)