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Which of the following is the correct syntax to add a new axis to the second dimension of a 2D numpy array arr?

easy📝 Syntax Q3 of 15
NumPy - Array Manipulation
Which of the following is the correct syntax to add a new axis to the second dimension of a 2D numpy array arr?
Aarr[np.newaxis, :, :]
Barr[:, :, np.newaxis]
Carr[:, np.newaxis, :]
Darr[:, :, :newaxis]
Step-by-Step Solution
Solution:

  1. Step 1: Understand array indexing for 2D arrays

    A 2D array has two axes: rows and columns. To add a new axis as the second dimension, we insert np.newaxis in the middle.

  2. Step 2: Check each option

    arr[:, np.newaxis, :] correctly adds newaxis as the second dimension. arr[np.newaxis, :, :] adds at the front, arr[:, :, np.newaxis] adds at the end, arr[:, :, :newaxis] is invalid syntax.

  3. Final Answer:

    arr[:, np.newaxis, :] -> Option C

  4. Quick Check:

    New axis in second position = arr[:, np.newaxis, :] [OK]
Quick Trick: Insert np.newaxis where you want the new dimension [OK]
Common Mistakes:
  • Using invalid syntax
  • Adding newaxis at wrong position
  • Confusing axis order

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