Reading a matrix (or array) from an excel file

Hi,

I'm relatively new to matlab, so sorry for very basic questions. I have 3 questions;

1) I want to read a matrix from an excel file and want to assign it a variable named as N_C. I added the following code in my .m file;

N_C=xlsread('C:\Users\Kajal Chopra\vibrations\free_vibrations_program\matlab_input_free_vibrations_1',1);

The values are in sheet 1.I'm also attaching the excel file for your reference. I do not want to tell Matlab that how many rows and columns the matrix has. My matrix has 3 rows and 3 columns. Is it possible that without telling Matlab the number of rows and columns, I carry out the filling up of my matrix/array "N_C" by reading it from xls file using xlsread.

2) Second, I want the end user to enter the xls file name from the command window and my .m file (as in the above location) should then open the file. That is, I do not want to give the file name as:

    'C:\Users\Kajal Chopra\vibrations\free_vibrations_program\matlab_input_free_vibrations_1'\

but a user specified file name from the command window.Is it possible?

3) Thirdly, how can I test of my N_C has been correctly assigned after the .m file has read it from xls file?

Thanks a million in advance.

Kajal

[Star Strider]

‘I'm also attaching the excel file for your reference.’

Not yet. Give it another go.

[kajalschopra]

Thanks and sorry.

See below. Now attached.

I have attached the xls file. See sheet 1.

0 0 0 1 0 0 2 0 0

The sheet 1 has above values.

I want:

N_C(1,1)= 0 (i.e. the value in A1) N_C(1,2)=0 (i.e. the value in B1) N_C(1,3)=0 (i.e. the value in C1)

N_C(2,1)=1 (i.e. the value in A2) N_C(2,2)=0 (i.e. the value in B2) N_C(2,3)=0 (i.e. the value in C2)

N_C(3,1)=2 (i.e. the value in A3) N_C(3,2)=0 (i.e. the value in B3) N_C(3,3)=0 (i.e. the value in C3)

[kajalschopra]

Can anyone please help, I need to sort it tonight

Answer 1

[Cedric]

Hi, try something along the following line:

 [filename, filepath] = uigetfile( '*.xls*' ) ;
 N_C = xlsread( fullfile( filepath, filename ), 'Sheet1' ) ;

Then, when you say "test if correct", what does it mean? You can test if the size is correct for example:

 assert( all( size( N_C ) == 3 ), 'Invalid N_C.' ) ;

if it has to be 3x3, but you'll have to define more precisely which other tests are relevant.

[kajalschopra]

Thanks. I have put in the .m file as follows.

N_C=xlsread('C:\Users\KajalChopra\vibrations\free_vibrations_program\matlab_input_free_vibrations_1','Sheet1');

Where /How can I print the contents of N_C to test if it is correct or not?

[kajalschopra]

Anyone or Cedric..please help.

[Cedric]

I provided you the 3 lines of code which ask the user to pick a file, read the file, and check that it is a 3x3 array:

 [filename, filepath] = uigetfile( '*.xls*' ) ;
 N_C = xlsread( fullfile( filepath, filename ), 'Sheet1' ) ;
 assert( all( size( N_C ) == 3 ), 'Invalid N_C.' ) ;

You can display the content of variables by typing their name in the command window, or by looking them up in the "Workspace" panel/window.