Beginner

Array Slicing and Strides

Beginner

~8 min

code completion

Array Slicing and Strides

NumPy arrays support rich slicing with the syntax arr[start:stop:step].

start: index to begin (inclusive)

stop: index to end (exclusive)

step: how many elements to skip

Examples:

arr = np.arange(10)  # [0 1 2 3 4 5 6 7 8 9]
arr[1:8:2]           # [1 3 5 7]  -- every 2nd element from index 1
arr[::-1]            # [9 8 7 ... 0]  -- reversed

Your task:

Implement extract_subarray(arr, start, stop, step) that returns arr[start:stop:step].

Example Tests

Every other element from index 1 to 8

Input: {"arr":[0,1,2,3,4,5,6,7,8,9],"step":2,"stop":8,"start":1}

Expected: [1,3,5,7]

Full array with step 1

Input: {"arr":[10,20,30,40,50],"step":1,"stop":5,"start":0}

Expected: [10,20,30,40,50]

Every third element

Input: {"arr":[0,1,2,3,4,5,6,7,8],"step":3,"stop":9,"start":0}

Expected: [0,3,6]

You can read the full problem statement above. Create a free account to run code in the browser, submit solutions, and track your progress.