Array Manipulation Functions

Functions for manipulating array shapes and combining arrays.

Example

import numpycore as np

arr = np.array([[1, 2, 3], [4, 5, 6]])

# Shape manipulation
reshaped = np.reshape(arr, (3, 2))
flattened = np.ravel(arr)
transposed = np.transpose(arr)

# Joining
stacked = np.stack([arr, arr])
concatenated = np.concatenate([arr, arr], axis=0)

Shape Manipulation

Function	Description	Example
reshape(a, newshape)	Give new shape to array
ravel(a)	Return contiguous flattened array	View
flatten(a)	Return flattened copy
squeeze(a)	Remove single-dimensional entries
expand_dims(a, axis)	Expand shape by inserting axis
atleast_1d(*arys)	Convert to at least 1-D	View
atleast_2d(*arys)	Convert to at least 2-D	View
atleast_3d(*arys)	Convert to at least 3-D	View
broadcast_to(array, shape)	Broadcast array to new shape

Transpose Operations

Function	Description	Example
transpose(a, axes)	Permute array dimensions
swapaxes(a, axis1, axis2)	Swap two axes
moveaxis(a, source, destination)	Move axes to new positions
rollaxis(a, axis, start)	Roll specified axis backwards

Joining Arrays

Function	Description	Example
concatenate((a1, a2, …), axis)	Join arrays along axis
stack(arrays, axis)	Join arrays along new axis
vstack(tup)	Stack arrays vertically (row-wise)
hstack(tup)	Stack arrays horizontally (column-wise)
dstack(tup)	Stack arrays depth-wise (3rd axis)
column_stack(tup)	Stack 1-D arrays as columns
row_stack(tup)	Stack arrays row-wise (alias for vstack)

Splitting Arrays

Function	Description	Example
split(ary, indices_or_sections, axis)	Split array into sub-arrays
array_split(ary, indices_or_sections, axis)	Split array (allows unequal division)
hsplit(ary, indices_or_sections)	Split horizontally (column-wise)
vsplit(ary, indices_or_sections)	Split vertically (row-wise)
dsplit(ary, indices_or_sections)	Split along third axis

Tiling and Repeating

Function	Description	Example
tile(A, reps)	Construct by repeating A
repeat(a, repeats, axis)	Repeat elements of array

Rearranging Elements

Function	Description	Example
flip(m, axis)	Reverse order of elements along axis
fliplr(m)	Flip left to right
flipud(m)	Flip up to down
rot90(m, k, axes)	Rotate 90 degrees
roll(a, shift, axis)	Roll elements along axis	View

Code Examples

The following examples are extracted from the test suite.

ravel (test_array_creation_extended.py:431)

    nc_result = test_bind.np.flatnonzero(nc_arr)

    assert_arrays_equal(np_result, nc_result, "flatnonzero", atol=0)


# ============================================================================
# NEW NUMPYCORE BINDINGS TESTS (ravel, meshgrid)
# ============================================================================

def test_ravel_numpycore_1d():
    """Test numpycore.ravel() with 1-D array"""
    np_arr = test_bind.np.array([1.0, 2.0, 3.0])
    nc_arr = test_bind.numpycore.array([1.0, 2.0, 3.0])

    np_result = test_bind.np.ravel(np_arr)
    nc_result = test_bind.numpycore.ravel(nc_arr)

    assert_arrays_equal(np_result, nc_result, "ravel_numpycore_1d")


def test_ravel_numpycore_2d():

atleast_1d (test_array_creation_extended.py:512)

    np_xv, np_yv, np_zv = test_bind.np.meshgrid(np_x, np_y, np_z, indexing='xy')
    nc_xv, nc_yv, nc_zv = test_bind.numpycore.meshgrid(nc_x, nc_y, nc_z, indexing='xy')

    assert_arrays_equal(np_xv, nc_xv, "meshgrid_numpycore_3d_xv")
    assert_arrays_equal(np_yv, nc_yv, "meshgrid_numpycore_3d_yv")
    assert_arrays_equal(np_zv, nc_zv, "meshgrid_numpycore_3d_zv")


def test_atleast_1d_numpycore():
    """Test numpycore.atleast_1d()"""
    np_arr = test_bind.np.array([1.0, 2.0, 3.0])
    nc_arr = test_bind.numpycore.array([1.0, 2.0, 3.0])

    np_result = test_bind.np.atleast_1d(np_arr)
    nc_result = test_bind.numpycore.atleast_1d(nc_arr)

    assert_arrays_equal(np_result, nc_result, "atleast_1d_numpycore")


def test_atleast_2d_numpycore():

atleast_2d (test_array_creation_extended.py:523)

    np_arr = test_bind.np.array([1.0, 2.0, 3.0])
    nc_arr = test_bind.numpycore.array([1.0, 2.0, 3.0])

    np_result = test_bind.np.atleast_1d(np_arr)
    nc_result = test_bind.numpycore.atleast_1d(nc_arr)

    assert_arrays_equal(np_result, nc_result, "atleast_1d_numpycore")


def test_atleast_2d_numpycore():
    """Test numpycore.atleast_2d()"""
    np_arr = test_bind.np.array([1.0, 2.0, 3.0])
    nc_arr = test_bind.numpycore.array([1.0, 2.0, 3.0])

    np_result = test_bind.np.atleast_2d(np_arr)
    nc_result = test_bind.numpycore.atleast_2d(nc_arr)

    assert_arrays_equal(np_result, nc_result, "atleast_2d_numpycore")


def test_atleast_3d_numpycore():

atleast_3d (test_array_creation_extended.py:534)

    np_arr = test_bind.np.array([1.0, 2.0, 3.0])
    nc_arr = test_bind.numpycore.array([1.0, 2.0, 3.0])

    np_result = test_bind.np.atleast_2d(np_arr)
    nc_result = test_bind.numpycore.atleast_2d(nc_arr)

    assert_arrays_equal(np_result, nc_result, "atleast_2d_numpycore")


def test_atleast_3d_numpycore():
    """Test numpycore.atleast_3d()"""
    np_arr = test_bind.np.array([[1.0, 2.0], [3.0, 4.0]])
    nc_arr = test_bind.numpycore.array([[1.0, 2.0], [3.0, 4.0]])

    np_result = test_bind.np.atleast_3d(np_arr)
    nc_result = test_bind.numpycore.atleast_3d(nc_arr)

    assert_arrays_equal(np_result, nc_result, "atleast_3d_numpycore")


# ============================================================================

roll (test_manipulation_phase17.py:66)

# ============================================================================
# ROLL TESTS
# ============================================================================

def test_roll_1d_positive():
    """Test rolling 1D array with positive shift"""
    np_arr = test_bind.np.arange(0, 10, 1, dtype='float64')
    nc_arr = test_bind.numpycore.arange(0, 10, 1)

    np_result = test_bind.np.roll(np_arr, 2)
    nc_result = test_bind.numpycore.roll(nc_arr, 2)

    assert_arrays_equal(np_result, nc_result, "roll_1d_positive_shift")


def test_roll_1d_negative():
    """Test rolling 1D array with negative shift"""
    np_arr = test_bind.np.arange(0, 10, 1, dtype='float64')
    nc_arr = test_bind.numpycore.arange(0, 10, 1)

    np_result = test_bind.np.roll(np_arr, -2)