Tensor shapes and reshaping in TensorFlow - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a tensor shape in TensorFlow?

A tensor shape is a list of integers that describes the size of the tensor in each dimension. For example, a shape of [3, 4] means the tensor has 3 rows and 4 columns.

beginner

How do you reshape a tensor in TensorFlow?

You use the tf.reshape() function, which changes the shape of a tensor without changing its data. You provide the tensor and the new shape you want.

intermediate

What does the '-1' argument mean in tf.reshape()?

The '-1' tells TensorFlow to automatically calculate the size of that dimension based on the other dimensions and the total number of elements.

beginner

Why is it important to keep the total number of elements the same when reshaping?

Because reshaping only changes the shape, not the data. The total number of elements must stay the same to avoid errors and keep data consistent.

beginner

What is the shape of a tensor created by tf.constant([[1, 2], [3, 4], [5, 6]])?

The shape is [3, 2] because there are 3 rows and 2 columns.

What does tf.reshape(tensor, [-1, 2]) do?

A Reshapes tensor to have 2 columns and automatically calculates rows

B Reshapes tensor to have 2 rows and automatically calculates columns

C Flattens the tensor into a 1D array

D Raises an error because -1 is invalid

The '-1' lets TensorFlow calculate the number of rows automatically, while 2 sets the number of columns.

If a tensor has shape [4, 5], how many elements does it have?

A 9

B 20

C 10

D None of the above

Multiply the dimensions: 4 * 5 = 20 elements.

Which function is used to check the shape of a tensor in TensorFlow?

A tf.size()

B tf.rank()

C tf.reshape()

D tf.shape()

tf.shape() returns the shape of the tensor as a tensor itself.

What happens if you try to reshape a tensor to a shape with a different total number of elements?

A TensorFlow raises an error

B TensorFlow automatically adjusts the data

C TensorFlow fills missing values with zeros

D TensorFlow ignores extra elements

Reshaping requires the total number of elements to stay the same; otherwise, TensorFlow raises an error.

What is the shape of a scalar tensor in TensorFlow?

A [0]

B [1]

C [] (empty shape)

D [1,1]

A scalar has no dimensions, so its shape is an empty list [].

Explain what tensor shape means and why it is important in TensorFlow.

Think about how shape tells you the size and layout of data.

Describe how to reshape a tensor and what rules must be followed during reshaping.

Consider how reshaping changes layout but not data.