这样的代码.. public class SongsManager {
// SDCard Path
final String MEDIA_PATH = new String("/sdcard/");//this will I switch to raw folder..
private ArrayList<HashMap<String, String>> songsList = new
我有这个矩阵mymat。我知道我可以做table((mymat[,"col1"])以获得col1中每件物品的编号。但是,如果col2中有唯一值,我只需要计数。对于低于mymat,我想这样的结果: app gg chh
1 2 1
mymat col1 col2
app d
app d
gg e
gg f
gg e
chh f
chh f
chh f