numpy.asarray#

numpy.asarray(a,dtype=None,order=None,*,device=None,copy=None,like=None)#

Convert the input to an array.

Parameters:
aarray_like

Input data, in any form that can be converted to an array. Thisincludes lists, lists of tuples, tuples, tuples of tuples, tuplesof lists and ndarrays.

dtypedata-type, optional

By default, the data-type is inferred from the input data.

order{‘C’, ‘F’, ‘A’, ‘K’}, optional

Memory layout. ‘A’ and ‘K’ depend on the order of input array a.‘C’ row-major (C-style),‘F’ column-major (Fortran-style) memory representation.‘A’ (any) means ‘F’ ifa is Fortran contiguous, ‘C’ otherwise‘K’ (keep) preserve input orderDefaults to ‘K’.

devicestr, optional

The device on which to place the created array. Default:None.For Array-API interoperability only, so must be"cpu" if passed.

New in version 2.0.0.

copybool, optional

IfTrue, then the object is copied. IfNone then the object iscopied only if needed, i.e. if__array__ returns a copy, if objis a nested sequence, or if a copy is needed to satisfy any ofthe other requirements (dtype,order, etc.).ForFalse it raises aValueError if a copy cannot be avoided.Default:None.

New in version 2.0.0.

likearray_like, optional

Reference object to allow the creation of arrays which are notNumPy arrays. If an array-like passed in aslike supportsthe__array_function__ protocol, the result will be definedby it. In this case, it ensures the creation of an array objectcompatible with that passed in via this argument.

New in version 1.20.0.

Returns:
outndarray

Array interpretation ofa. No copy is performed if the inputis already an ndarray with matching dtype and order. Ifa is asubclass of ndarray, a base class ndarray is returned.

See also

asanyarray

Similar function which passes through subclasses.

ascontiguousarray

Convert input to a contiguous array.

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

Existing arrays are not copied:

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

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

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

Contrary toasanyarray, ndarray subclasses are not passed through:

>>>issubclass(np.recarray,np.ndarray)True>>>a=np.array([(1.,2),(3.,4)],dtype='f4,i4').view(np.recarray)>>>np.asarray(a)isaFalse>>>np.asanyarray(a)isaTrue
On this page