function?entro?=?entro_calculated（x）
????%?%?calculate?the?entropy
????Elem_x?=?unique（x）;?%?find?all?possible?elements?of?Y
????num_x?=?length（Elem_x）;?%?the?number?of?possible?cases?of?Y
????denominator?=?length（x）;
????prob?=?zeros（num_x1）;
????Info?=?zeros（num_x1）;
????for?i?=?1:num_x
????????index?=?（x?==?Elem_x（i））;
????????prob（i）?=?sum（index）/denominator;
????????Info（i）?=?prob（i）*log（prob（i））;
????end

????entro?=?-sum（prob.*Info）/log（2）;?%?unified?as?bit
end

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2014-03-22?19:26??Maching?Learning\
?????文件????????6250??2014-03-07?20:00??Maching?Learning\balance-scale.data
?????文件????????2222??2014-03-07?20:00??Maching?Learning\balance-scale.names
?????文件???????15777??2014-03-12?16:25??Maching?Learning\balance_scale.png
?????文件????????5089??2014-03-12?16:41??Maching?Learning\balloon.png
?????文件?????????160??2014-03-11?22:58??Maching?Learning\balloons.data
?????文件????????1104??2014-03-07?19:59??Maching?Learning\balloons.names
?????文件?????????488??2014-03-05?16:21??Maching?Learning\entro_calculated.m
?????文件?????????493??2014-03-05?20:20??Maching?Learning\E_category.m
?????文件?????????254??2014-03-12?16:26??Maching?Learning\GolfPlay.mat
?????文件????????4388??2014-03-12?16:27??Maching?Learning\GolfPlay.png
?????文件?????????447??2014-03-12?16:11??Maching?Learning\ID3_tree.m
?????文件?????????408??2014-03-07?20:06??Maching?Learning\lenses.data
?????文件????????1644??2014-03-07?20:06??Maching?Learning\lenses.names
?????文件????????5222??2014-03-12?16:45??Maching?Learning\lenses.png
?????文件?????????123??2014-03-12?15:37??Maching?Learning\preproc_balance_scale.asv
?????文件?????????192??2014-03-12?16:11??Maching?Learning\preproc_balance_scale.m
?????文件?????????226??2014-03-12?16:40??Maching?Learning\preproc_balloons.m
?????文件??????????62??2014-03-12?16:27??Maching?Learning\preproc_GolfPlay.m
?????文件??????????83??2014-03-12?16:32??Maching?Learning\preproc_lenses.m
?????文件????????2113??2014-03-12?00:45??Maching?Learning\recurrent_step.asv
?????文件????????2119??2014-03-12?00:46??Maching?Learning\recurrent_step.m