Week 1 Quiz :Natural Language Processing in TensorFlow (DeepLearning.AI TensorFlow Developer Professional Certificate) Answers 2025
1. Question 1
In the lectures, what is the name of the layer used to generate the vocabulary?
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❌ Tokenizer
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❌ TextTokenizer
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❌ WordTokenizer
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✅ TextVectorization
Explanation: TensorFlow’s TextVectorization layer builds the vocabulary and vectorizes text.
2. Question 2
Once you have generated a vocabulary, how do you encode a sentence into an integer sequence?
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✅ Pass the string to the adapted TextVectorization layer.
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❌ get_vocabulary()
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❌ texts_to_tokens()
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❌ texts_to_sequences()
Explanation: The TextVectorization layer itself is callable.
Usage:
vectorize_layer("this is a sentence")
3. Question 3
How do you handle sequences of different lengths?
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✅ Use the pad_sequences function from tf.keras.utils
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❌ pad_sequences method inside TextVectorization
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❌ pad_sequences property on input layer
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❌ dynamic_length input layer
Explanation: Use tf.keras.utils.pad_sequences() to ensure equal sequence length.
4. Question 4
What happens when encoding a word not in the vocabulary?
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❌ Sequencing ends
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❌ Replaced by most common token
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✅ An out-of-vocabulary token (OOV token) is used
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❌ Replaced by zero
Explanation: OOV token (usually index 1) represents unknown words.
5. Question 5
How to pad at the end of a sequence?
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✅
padding='post'in pad_sequences -
❌ padding=’after’
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❌ padding method with ‘after’
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❌ padding method with ‘post’
Explanation:
pad_sequences(..., padding='post')
6. Question 6
Convert a list of strings into integer sequences?
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❌ vectorize_layer.fit(sentences)
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❌ vectorize_layer.tokenize(sentences)
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❌ vectorize_layer.fit_to_text(sentences)
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✅ vectorize_layer(sentences)
Explanation: Call the layer directly to vectorize text.
7. Question 7
Default behavior of pad_sequences?
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✅ Pad to the longest sequence by adding zeros at the beginning
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❌ Pad zeros at the end
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❌ Leave unchanged
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❌ Crop to shortest
Explanation: Default is:
padding='pre'
truncating='pre'
8. Question 8
How does TextVectorization standardize strings by default?
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❌ Stripping punctuation
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❌ Alphabetical order
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❌ Lowercasing only
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✅ Lowercasing AND stripping punctuation
Explanation: Default standardization = lower_and_strip_punctuation.
🧾 Summary Table
| Q# | Correct Answer | Key Concept |
|---|---|---|
| 1 | TextVectorization | Builds vocabulary |
| 2 | vectorize_layer(string) | Encodes text |
| 3 | pad_sequences | Making sequences equal length |
| 4 | OOV token | Handling unknown words |
| 5 | padding=’post’ | Post-padding |
| 6 | vectorize_layer(sentences) | Convert list of strings |
| 7 | Pad with zeros at beginning | Default pad_sequences behavior |
| 8 | lowercase + strip punctuation | Default standardization |