How do you access specific columns in a NumPy multidimensional array?

Accessing Columns in NumPy Multidimensional Arrays

Given a NumPy multidimensional array, retrieving specific columns can be achieved efficiently using indexing techniques. To access the ith column, utilize the following syntax:

<code class="python">array[:, i]</code>

For example:

<code class="python">test = np.array([[1, 2], [3, 4], [5, 6]])
test[:, 0]  # Accesses the first column</code>

which outputs:

array([1, 3, 5])

Conversely, to access the ith row, use:

<code class="python">array[i, :]</code>

For example:

<code class="python">test[0, :]  # Accesses the first row</code>

which outputs:

array([1, 2])

Refer to the NumPy reference's Indexing section for further details. This operation is generally efficient, particularly in comparison to looping over individual elements.

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