What r the sayings which mean "to learn something, but without understanding it"?

Information goes in one ear and comes out the other

 "A little learning is a dang'rous thing; / Drink deep, or taste not the Pierian spring." ...

That basically would be memorization.

Instinct the need to know is the right to know, do it first understand it after. An idiot savant is one that does not need to understand because he is possessed by one of his remote ancestors or other who already knows. 

To parrot, or regurgitate.

If you're looking for quotes, there are any number of them about the difference between knowledge and wisdom that apply.  My favorites are:

Knowledge is knowing the street is one-way.  Wisdom is looking both ways anyway.

Knowledge is knowing that a tomato is a fruit.  Wisdom is not putting one in a fruit salad.

rote memorization

Information goes in one ear and comes out the other

'You can know something, without understanding it'?