Failed on converting date string to date number

hi all,

I have this code that I need to plot date data time vs power from excel, my code is as follow:

    [num,T,vT] = xlsread('excel.xls','Sheet1');      %excel file
   x = T(:,1);                                       % Time column
   y = num(:,4);                                     % power column  
%    x1=datenum(0,0,0,0,x,0);
   x1=datenum(x,'HH:MM');
    plot(handles.axes,x1,y)

but I am getting this error:

??? DATENUM failed. Error using ==> dtstr2dtnummx Failed on converting date string to date number.

so how can I overcome this problem ??? please help..

Sam

Answer 1

[Walter Roberson]

One or more of the times being input does not have the expected format.

for K = 1 : length(x)
  try
    x1 = datenum(x{K}, 'HH:MM');
  catch 
    fprintf('Entry #%d is not valid, is |%s|\n', K, x{K});
  end
end

[Samer Husam]

i am getting this error while i am using ur way...

??? Index exceeds matrix dimensions.

Error in ==> simpletab>pushbutton1_Callback at 1604 fprintf('Entry #%d is not valid, is %s\n', K, x{K});

why this error is occur ?

[Walter Roberson]

Odd. Could you show us

size(x)

length(x)

[Samer Husam]

its:

for k = 1:35
  try
    x1 = datenum(x{K}, 'HH:MM');
  catch 
    fprintf('Entry #%d is not valid, is |%s|\n', K, x{K});
  end
end

[Walter Roberson]

What is size(x) ? If it does not have at least 35 elements then you would get that error message.

[Samer Husam]

what do u mean by size(x)? what is represent ?

[Walter Roberson]

http://www.mathworks.com/help/techdoc/ref/size.html

d = size(X) returns the sizes of each dimension of array X in a vector d with ndims(X) elements. If X is a scalar, which MATLAB software regards as a 1-by-1 array, size(X) returns the vector [1 1].