//类工厂方法。nsmutalearray * array =[nsmutalearray array];nsmutalraray * a2 =[nsmutalrayrayarraywith objects:@ " look ",nil];//加上原素。[ArrayaddObject:@ " heh edda "];[a2 addobject:@ " Gaga g "];//删掉全部原素。[a2 removeallobjects];//删掉特定的原素。[a2removeObjectAtIndex:1];//能够建立,但不可