# Q1 (2 marks)

Subject: Natural Language Processing

Exam: M2

Reader: https://deep-learning-study-room.vercel.app/nlp/#m2/mocks/mock-a/q1

Canonical: https://deep-learning-study-room.vercel.app/read/nlp/m2/mocks/mock-a--q1/

M2 · confirmed 2 + 2 + any two of 3 + 3 + 3 · worked practice

### Q1

For “we study language models”, list the unigrams, bigrams and trigrams. Do not add boundary markers. (2 marks)

**Given**

Four tokens in the stated order.

**To find**

All contiguous n-grams for n=1,2,3.

### Formula and why it applies



$$
\#\text{ n-grams}=T-n+1
$$



T is the number of tokens. Slide a window of n consecutive tokens, one position at a time.

### Solution

#### Step 1. Unigrams, window size 1

(we), (study), (language), (models); count=4.

#### Step 2. Bigrams, window size 2

(we study), (study language), (language models); count=4−2+1=3.

#### Step 3. Trigrams, window size 3

(we study language), (study language models); count=4−3+1=2.

4 unigrams, 3 bigrams and 2 trigrams, listed above.