At the beginning and end of the emojify programming exercise, it is mentioned that negative sampling is used:
“[This notebook] Describe how negative sampling learns word vectors more efficiently than other methods”
But I don’t see where it was used 
. Can anyone help me point this out please.
The negative sampling method is discussed in the lectures. It’s built-in with how word2vec is trained, which we use in the programming assignment. But isn’t specifically discussed within the programming assignment.
but personally i didn’t learn “how negative sampling learns word vectors more efficiently than other methods” through the programming exercise though. maybe we should consider changing the description here.
That is a good suggestion.