`numpy:expand_dims`

Signature

def expand_dims(a, axis)

Expand the shape of an array.

Insert a new axis that will appear at the axis position in the expanded array shape.

a : array_like: Input array.
axis : int or tuple of ints: Position in the expanded axes where the new axis (or axes) is placed.
deprecated 1.13.0
Passing an axis where axis > a.ndim will be treated as axis == a.ndim, and passing axis < -a.ndim - 1 will be treated as axis == 0. This behavior is deprecated.

import numpy as np
x = np.array([1, 2])
x.shape

✓

(2,)

The following is equivalent to ``x[np.newaxis, :]`` or ``x[np.newaxis]``:

y = np.expand_dims(x, axis=0)
y
y.shape

✓

(1, 2)

The following is equivalent to ``x[:, np.newaxis]``:

y = np.expand_dims(x, axis=1)
y
y.shape

✓

(2, 1)

``axis`` may also be a tuple:

y = np.expand_dims(x, axis=(0, 1))
y

✓

array([[[1, 2]]])

y = np.expand_dims(x, axis=(2, 0))
y

✓

array([[[1],
        [2]]])

Note that some examples may use ``None`` instead of ``np.newaxis``. These are the same objects:

np.newaxis is None

✓

True