Different results from STRREAD() for reading strings - arrays

Question

I have a date cell array which is read from a csv file. The format is below:
date =
'2008.12.01'
'2008.12.02'
'2008.12.03'
'2008.12.04'
'2008.12.05'
... ...
And I want to:
turn the cell array to a string array,
use the strread() to read its "yyyy","mm" and "dd" value into 3 double array [year,mm,dd],
use the datenummx() to turn [year,mm,dd] into date seriel num.
After i use
date = char(date);
the date array become like this:
date =
2008.12.01
2008.12.02
2008.12.03
2008.12.04
2008.12.05
... ...
which I think the result is what i want...
But after I use the strread(), it gives me odd result.
[year,month,day]=strread(date,'%d%d%d','delimiter','.');
year =
-1
0
0
0
0
... ...
BUT if I use the code below, the strread() can give me the right answer:
s = sprintf('2008.12.01')
s =
2008.12.01
[year,month,day]=strread(s,'%d%d%d','delimiter','.')
year =
2008
month =
12
day =
1
And I checked in the matlab that both the "date" and "s" is a char array.(by using function 'ischar' and simply display both)...
But why do the strread() give differnt results?
Can anyone answer?
by the way, I use the MatLab v6.5.(for my own reason, so please don't comment by asking "why not use a higher version")....

Answer 1

Your problem is this line:
date = char(date);
It does not create an array of strings, there is no array of strings in matlab. It creates an array of chars. As you already noticed, your strread-line is fine if you input a single date, so input each date form your original cell array individually:
for idx=1:numel(date)
[year(idx),month(idx),day(idx)]=strread(date{idx},'%d%d%d','delimiter','.');
end
Preallocation of year, month and day improves the performance.