what is the use of the symbol '*' in the function named fullfile?

Hi,what is the significance of the asterik symbol '*' in the following statement...

filePattern = fullfile(myFolder, '*.jpg');

Answer 1

[Walter Roberson]

The meaning is the literal character '*' . fullfile() does not process the arguments: it just puts together a file name using the exact strings you pass in. You could pass in nonsense strings and it wouldn't care.

Now, the function that you pass the completed string to might care. The context suggests the string is probably being passed to the dir() function. dir() would pass the string to the operating system, which would interpret it in operating-system specific ways. Usually '*' is interpreted as a "wildcard" meaning "any number of any characters, but excluding the directory separator". In unix systems, the "null character" (decimal value 0) is also excluded.

[Manoj Murali]

oh...thanq sir...but one more doudt....

suppose,

jpgfiles=dir(filePattern);

h=length(jpgfiles);

now..wat does the above two statements mean..??

[Walter Roberson]

dir() returns a structure of information about the files or directories found. See the documentation for dir() for details.

length() of the result of dir() is the number of files or directories found.

Answer 2

[Dr. Seis]

It means that any file whose name is something.jpg will be used. For example if:

myFolder = '/home/yourfolder';

then

filePattern = fullfile(myFolder,'*.jpg');

will return

filePattern =

'/home/yourfolder/*.jpg'

An then

>> dir(filePattern)

might return something like:

pic001.jpg
pic002.jpg
pic003.jpg
pic004.jpg

[Manoj Murali]

oh...thanq sir...but one more doudt....

suppose,

jpgfiles=dir(filepattern);

h=length(jpgfiles);

now..wat does the above two statements mean..??