numpy.asarray — NumPy v1.11 Manual (original) (raw)

numpy.asarray(a, dtype=None, order=None)[source]

Convert the input to an array.

Parameters: a : array_like Input data, in any form that can be converted to an array. This includes lists, lists of tuples, tuples, tuples of tuples, tuples of lists and ndarrays. dtype : data-type, optional By default, the data-type is inferred from the input data. order : {‘C’, ‘F’}, optional Whether to use row-major (C-style) or column-major (Fortran-style) memory representation. Defaults to ‘C’.
Returns: out : ndarray Array interpretation of a. No copy is performed if the input is already an ndarray. If a is a subclass of ndarray, a base class ndarray is returned.

See also

asanyarray

Similar function which passes through subclasses.

ascontiguousarray

Convert input to a contiguous array.

asfarray

Convert input to a floating point ndarray.

asfortranarray

Convert input to an ndarray with column-major memory order.

asarray_chkfinite

Similar function which checks input for NaNs and Infs.

fromiter

Create an array from an iterator.

fromfunction

Construct an array by executing a function on grid positions.

Examples

Convert a list into an array:

a = [1, 2] np.asarray(a) array([1, 2])

Existing arrays are not copied:

a = np.array([1, 2]) np.asarray(a) is a True

If dtype is set, array is copied only if dtype does not match:

a = np.array([1, 2], dtype=np.float32) np.asarray(a, dtype=np.float32) is a True np.asarray(a, dtype=np.float64) is a False

Contrary to asanyarray, ndarray subclasses are not passed through:

issubclass(np.matrix, np.ndarray) True a = np.matrix([[1, 2]]) np.asarray(a) is a False np.asanyarray(a) is a True