Extracting the numbers from file names and listing them in a column

Hi all ,

I have png files like this ;

Rpma26siatBz 9.500000 Bx 0.000000mT WWait 2.000000Sec.Bzat9.5mT83.png,

Rpma26siatBz 9.500000 Bx 100.000000mT WWait 1.000000Sec.Bzat9.5mT85.png

and so on

I want to extract numbers 0.000000 from first file ,100.000000 from second file etc .and put in one column.

And again extract the numbers 2.000000 from first file,1.000000 from second file etc. and put in another column.

I tried writing the code like this but it didnt work ( I mean I got NAN)? It would be great if you share any ideas for doing it .

thank you

clear all;
close all;
clc;
listI=dir('*.png');
B=[];

for i=1:length(listI);
    n=listI(i);
    A1 =n(1:end-26);
    A2 = n(1:end-19);
    x1= str2double(A1);
    x2=str2double(A2);
    Bx=[B;(x1),(x2)];
    
    
end

Answer 1

[Stephen23]

C = {'Rpma26siatBz  9.500000 Bx 0.000000mT WWait 2.000000Sec.Bzat9.5mT83.png',...
   'Rpma26siatBz  9.500000 Bx 100.000000mT WWait 1.000000Sec.Bzat9.5mT85.png'};
M = sscanf([C{:}],'Rpma%*dsiatBz%*f Bx%fmT WWait%fSec.Bzat%*fmT%*d.png',[2,Inf]).'

M = 2×2

0 2 100 1

Or

W = regexp(C,'(?<=\s)\d+\.\d+(?=[A-Za-z])','match');
M = str2double(vertcat(W{:}))

M = 2×2

0 2 100 1

[Babu Sankhi]

Thanks but I have to do it for 100 png files so I tried it by using for loop this way ,it didn't work? Can you help me more. I am sorry I am new in matlab.

listI=dir('*.png');


for i=1:length(listI);
    C=listI(i);
    W = regexp(C,'(?<=\s)\d+\.\d+(?=[A-Za-z])','match');
    M = str2double(vertcat(W{:}));
    
end

[Stephen23]

Neither of the solutions I gave in my answer require a loop. Try them like this:

S = dir('*.png');
M = sscanf([S.name],..)
%          ^^^^^^^^ changed input

or

W = regexp({S.name},..)
%          ^^^^^^^^ changed input

[Babu Sankhi]

Thanks , But it does not work for these png files!! Can you help me more?

C = {'Rpma26siatz  -9.600000 Bx -100.000000mT Waait 600.000000SecBzat-9.6mTDAQ02.png','Rpma26siatz  -9.600000 Bx 40.000000mT Waait 2000.000000SeBzat-9.6mTDAQ45.png',...
   'Rpma26siatz  -9.600000 Bx 130.000000mT Waait 1500.000000SeBzat-9.6mTDAQ27.png',};
M = sscanf([C{:}],'Rpma%*fsiatz%*f Bx%fmT Waait%fSeBzat%*fmTDAQ%*d.png',[2,Inf]).'

[Stephen23]

"..it does not work for these png files"

The first name has extra character/s which do not match the format string:

%...SecBzat.... 1st name
%     ^         not in format string!
%...SeBzat....  2nd and 3rd names
%...SeBzat....  format string

sscanf will stop parsing the string as soon as it reaches that 'c' character, because it does not match the format string and so does not know how to handle it. You can perform more flexible matching like this:

C = {'Rpma26siatz  -9.600000 Bx -100.000000mT Waait 600.000000SecBzat-9.6mTDAQ02.png',...
    'Rpma26siatz  -9.600000 Bx 40.000000mT Waait 2000.000000SeBzat-9.6mTDAQ45.png',...
    'Rpma26siatz  -9.600000 Bx 130.000000mT Waait 1500.000000SeBzat-9.6mTDAQ27.png'};
M = sscanf([C{:}],'%*[ A-Za-z.]%f',[6,Inf]).'

M = 3×6

26 -9.6 -100 600 -9.6 2 26 -9.6 40 2000 -9.6 45 26 -9.6 130 1500 -9.6 27

[Babu Sankhi]

thanks for your great help