How to search and extract text segment from a character array?

I have some text in a variable namely 'hdr'. From the workplace I see the type of the variable being a character array.

From the text stored in the variable, I want to extract the value of 'testdevice.x' and 'testdevice.y'. I tried strfind() but it says "TEXT must be a string or cell array of strings."

Thanks for helping

[dpb]

Convert to either cellstr() or string() first, then regexp is vectorized to find more general patterns or use the new(ish) string...

hdr=string(hdr);                                        % convert to string
ix=contains(hdr,"device.x")| contains(hdr,"device.y");  % find device.x|y
device=hdr(ix);                                         % return those lines

then can parse those lines for the data

[Md Nur Kutubul Alam]

It says "Undefined function 'string' for input arguments of type 'char'."

Answer 1

[Andrei Bobrov]

c = cellstr(hdr);
out = str2double(...
    regexp(c,'(?<=(testdevice\.x|testdevice\.у)\s*\:\s*)\-?\d*','match','once'));
out = out(~isnan(out));