class numpy.ndarray[source]
An array object represents a multidimensional, homogeneous array of fixed-size items. An associated data-type object describes the format of each element in the array (its byte-order, how many bytes it occupies in memory, whether it is an integer, a floating point number, or something else, etc.)
Arrays should be constructed using array
, zeros
or empty
(refer to the See Also section below). The parameters given here refer to a low-level method (ndarray(...)
) for instantiating an array.
For more information, refer to the numpy
module and examine the the methods and attributes of an array.
Parameters: |
(for the __new__ method; see Notes below) shape : tuple of ints Shape of created array. dtype : data-type, optional Any object that can be interpreted as a numpy data type. buffer : object exposing buffer interface, optional Used to fill the array with data. offset : int, optional Offset of array data in buffer. strides : tuple of ints, optional Strides of data in memory. order : {‘C’, ‘F’}, optional Row-major (C-style) or column-major (Fortran-style) order. |
---|
See also
There are two modes of creating an array using __new__
:
buffer
is None, then only shape
, dtype
, and order
are used.buffer
is an object exposing the buffer interface, then all keywords are interpreted.No __init__
method is needed because the array is fully initialized after the __new__
method.
These examples illustrate the low-level ndarray
constructor. Refer to the See Also
section above for easier ways of constructing an ndarray.
First mode, buffer
is None:
>>> np.ndarray(shape=(2,2), dtype=float, order='F') array([[ -1.13698227e+002, 4.25087011e-303], [ 2.88528414e-306, 3.27025015e-309]]) #random
Second mode:
>>> np.ndarray((2,), buffer=np.array([1,2,3]), ... offset=np.int_().itemsize, ... dtype=int) # offset = 1*itemsize, i.e. skip first element array([2, 3])
T | Same as self.transpose(), except that self is returned if self.ndim < 2. |
data | Python buffer object pointing to the start of the array’s data. |
dtype | Data-type of the array’s elements. |
flags | Information about the memory layout of the array. |
flat | A 1-D iterator over the array. |
imag | The imaginary part of the array. |
real | The real part of the array. |
size | Number of elements in the array. |
itemsize | Length of one array element in bytes. |
nbytes | Total bytes consumed by the elements of the array. |
ndim | Number of array dimensions. |
shape | Tuple of array dimensions. |
strides | Tuple of bytes to step in each dimension when traversing an array. |
ctypes | An object to simplify the interaction of the array with the ctypes module. |
base | Base object if memory is from some other object. |
all ([axis, out, keepdims]) | Returns True if all elements evaluate to True. |
any ([axis, out, keepdims]) | Returns True if any of the elements of a evaluate to True. |
argmax ([axis, out]) | Return indices of the maximum values along the given axis. |
argmin ([axis, out]) | Return indices of the minimum values along the given axis of a . |
argpartition (kth[, axis, kind, order]) | Returns the indices that would partition this array. |
argsort ([axis, kind, order]) | Returns the indices that would sort this array. |
astype (dtype[, order, casting, subok, copy]) | Copy of the array, cast to a specified type. |
byteswap (inplace) | Swap the bytes of the array elements |
choose (choices[, out, mode]) | Use an index array to construct a new array from a set of choices. |
clip ([min, max, out]) | Return an array whose values are limited to [min, max] . |
compress (condition[, axis, out]) | Return selected slices of this array along given axis. |
conj () | Complex-conjugate all elements. |
conjugate () | Return the complex conjugate, element-wise. |
copy ([order]) | Return a copy of the array. |
cumprod ([axis, dtype, out]) | Return the cumulative product of the elements along the given axis. |
cumsum ([axis, dtype, out]) | Return the cumulative sum of the elements along the given axis. |
diagonal ([offset, axis1, axis2]) | Return specified diagonals. |
dot (b[, out]) | Dot product of two arrays. |
dump (file) | Dump a pickle of the array to the specified file. |
dumps () | Returns the pickle of the array as a string. |
fill (value) | Fill the array with a scalar value. |
flatten ([order]) | Return a copy of the array collapsed into one dimension. |
getfield (dtype[, offset]) | Returns a field of the given array as a certain type. |
item (*args) | Copy an element of an array to a standard Python scalar and return it. |
itemset (*args) | Insert scalar into an array (scalar is cast to array’s dtype, if possible) |
max ([axis, out]) | Return the maximum along a given axis. |
mean ([axis, dtype, out, keepdims]) | Returns the average of the array elements along given axis. |
min ([axis, out, keepdims]) | Return the minimum along a given axis. |
newbyteorder ([new_order]) | Return the array with the same data viewed with a different byte order. |
nonzero () | Return the indices of the elements that are non-zero. |
partition (kth[, axis, kind, order]) | Rearranges the elements in the array in such a way that value of the element in kth position is in the position it would be in a sorted array. |
prod ([axis, dtype, out, keepdims]) | Return the product of the array elements over the given axis |
ptp ([axis, out]) | Peak to peak (maximum - minimum) value along a given axis. |
put (indices, values[, mode]) | Set a.flat[n] = values[n] for all n in indices. |
ravel ([order]) | Return a flattened array. |
repeat (repeats[, axis]) | Repeat elements of an array. |
reshape (shape[, order]) | Returns an array containing the same data with a new shape. |
resize (new_shape[, refcheck]) | Change shape and size of array in-place. |
round ([decimals, out]) | Return a with each element rounded to the given number of decimals. |
searchsorted (v[, side, sorter]) | Find indices where elements of v should be inserted in a to maintain order. |
setfield (val, dtype[, offset]) | Put a value into a specified place in a field defined by a data-type. |
setflags ([write, align, uic]) | Set array flags WRITEABLE, ALIGNED, and UPDATEIFCOPY, respectively. |
sort ([axis, kind, order]) | Sort an array, in-place. |
squeeze ([axis]) | Remove single-dimensional entries from the shape of a . |
std ([axis, dtype, out, ddof, keepdims]) | Returns the standard deviation of the array elements along given axis. |
sum ([axis, dtype, out, keepdims]) | Return the sum of the array elements over the given axis. |
swapaxes (axis1, axis2) | Return a view of the array with axis1 and axis2 interchanged. |
take (indices[, axis, out, mode]) | Return an array formed from the elements of a at the given indices. |
tobytes ([order]) | Construct Python bytes containing the raw data bytes in the array. |
tofile (fid[, sep, format]) | Write array to a file as text or binary (default). |
tolist () | Return the array as a (possibly nested) list. |
tostring ([order]) | Construct Python bytes containing the raw data bytes in the array. |
trace ([offset, axis1, axis2, dtype, out]) | Return the sum along diagonals of the array. |
transpose (*axes) | Returns a view of the array with axes transposed. |
var ([axis, dtype, out, ddof, keepdims]) | Returns the variance of the array elements, along given axis. |
view ([dtype, type]) | New view of array with the same data. |
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Licensed under the NumPy License.
https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.ndarray.html