Regular Expressions using regexp

Hello, I have some problem with understanding regexp expression

I have some names: ["T_24_UZK500.txt"; "FWD_T80_UZK500.txt"; "T80_UZK700.txt"]

how can I get numbers after "T" and after "UZK"?

I need a rule that will describe only the numbers after the designated patterns.

[Adam Danz]

Are "T" and "UZK" the only possible letters in the names?

[Eduard Mazur]

It's variable symbols which are defined earlier.

I mean, I have filenames (string) and patterns (variable inside this names). With this information I need extract numerical vallues after variables..

Answer 1

[Stephen23]

Matching only integer numbers after 'UZK' or 'T_' (it is unclear in your question if the underscore is permitted or not, but the regular expression below is easy to adapt):

>> S = {'T_24_UZK500.txt';'FWD_T80_UZK500.txt';'T80_UZK700.txt'};
>> C = regexp(S,'(?<=(T_?|UZK))\d+','match');
>> C{:}
ans = 
    '24'    '500'
ans = 
    '80'    '500'
ans = 
    '80'    '700'

Or simply by matching any integer numbers:

>> C = regexp(S,'\d+','match');
>> C{:}
ans = 
    '24'    '500'
ans = 
    '80'    '500'
ans = 
    '80'    '700'

[Eduard Mazur]

Thank you Stephen for solution,

it's working good,

but can we turn 'T' and 'UZK' inside in a variable?

I want to try it with dynamic field names..

[Adam Danz]

Small change from Stephen's solution: here you can list the potential patterns and the expression will be created according to your list. Also, underscores are removed ahead of time.

 S = {'T_24_UZK500.txt';'FWD_T80_UZK500.txt';'T80_UZK700.txt'};
 patterns = {'T', 'UZK'}; 
 
 exp = ['(?<=(', strjoin(patterns,'|') ,'))\d+']; 
 % Remove all underscores (if any)
 S = strrep(S, '_', '');
 C = regexp(S, exp, 'match'); % use regexpi() to ignore case

[Eduard Mazur]

Thanks for your helping!

This solution fit for me.

[madhan ravi]

Using exp as a variable name is not a good idea it would thwart the inbuilt function exp()