Vous êtes un professionnel et vous avez besoin d'une formation ?
Mise en oeuvre d'IHM
avec Qt et PySide6
Voir le programme détaillé
Module « numpy.matlib »
Signature de la fonction arange
Description
help(numpy.matlib.arange)
arange([start,] stop[, step,], dtype=None, *, device=None, like=None)
Return evenly spaced values within a given interval.
``arange`` can be called with a varying number of positional arguments:
* ``arange(stop)``: Values are generated within the half-open interval
``[0, stop)`` (in other words, the interval including `start` but
excluding `stop`).
* ``arange(start, stop)``: Values are generated within the half-open
interval ``[start, stop)``.
* ``arange(start, stop, step)`` Values are generated within the half-open
interval ``[start, stop)``, with spacing between values given by
``step``.
For integer arguments the function is roughly equivalent to the Python
built-in :py:class:`range`, but returns an ndarray rather than a ``range``
instance.
When using a non-integer step, such as 0.1, it is often better to use
`numpy.linspace`.
See the Warning sections below for more information.
Parameters
----------
start : integer or real, optional
Start of interval. The interval includes this value. The default
start value is 0.
stop : integer or real
End of interval. The interval does not include this value, except
in some cases where `step` is not an integer and floating point
round-off affects the length of `out`.
step : integer or real, optional
Spacing between values. For any output `out`, this is the distance
between two adjacent values, ``out[i+1] - out[i]``. The default
step size is 1. If `step` is specified as a position argument,
`start` must also be given.
dtype : dtype, optional
The type of the output array. If `dtype` is not given, infer the data
type from the other input arguments.
device : str, optional
The device on which to place the created array. Default: ``None``.
For Array-API interoperability only, so must be ``"cpu"`` if passed.
.. versionadded:: 2.0.0
like : array_like, optional
Reference object to allow the creation of arrays which are not
NumPy arrays. If an array-like passed in as ``like`` supports
the ``__array_function__`` protocol, the result will be defined
by it. In this case, it ensures the creation of an array object
compatible with that passed in via this argument.
.. versionadded:: 1.20.0
Returns
-------
arange : ndarray
Array of evenly spaced values.
For floating point arguments, the length of the result is
``ceil((stop - start)/step)``. Because of floating point overflow,
this rule may result in the last element of `out` being greater
than `stop`.
Warnings
--------
The length of the output might not be numerically stable.
Another stability issue is due to the internal implementation of
`numpy.arange`.
The actual step value used to populate the array is
``dtype(start + step) - dtype(start)`` and not `step`. Precision loss
can occur here, due to casting or due to using floating points when
`start` is much larger than `step`. This can lead to unexpected
behaviour. For example::
>>> np.arange(0, 5, 0.5, dtype=int)
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0])
>>> np.arange(-3, 3, 0.5, dtype=int)
array([-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8])
In such cases, the use of `numpy.linspace` should be preferred.
The built-in :py:class:`range` generates :std:doc:`Python built-in integers
that have arbitrary size <python:c-api/long>`, while `numpy.arange`
produces `numpy.int32` or `numpy.int64` numbers. This may result in
incorrect results for large integer values::
>>> power = 40
>>> modulo = 10000
>>> x1 = [(n ** power) % modulo for n in range(8)]
>>> x2 = [(n ** power) % modulo for n in np.arange(8)]
>>> print(x1)
[0, 1, 7776, 8801, 6176, 625, 6576, 4001] # correct
>>> print(x2)
[0, 1, 7776, 7185, 0, 5969, 4816, 3361] # incorrect
See Also
--------
numpy.linspace : Evenly spaced numbers with careful handling of endpoints.
numpy.ogrid: Arrays of evenly spaced numbers in N-dimensions.
numpy.mgrid: Grid-shaped arrays of evenly spaced numbers in N-dimensions.
:ref:`how-to-partition`
Examples
--------
>>> import numpy as np
>>> np.arange(3)
array([0, 1, 2])
>>> np.arange(3.0)
array([ 0., 1., 2.])
>>> np.arange(3,7)
array([3, 4, 5, 6])
>>> np.arange(3,7,2)
array([3, 5])
Vous êtes un professionnel et vous avez besoin d'une formation ?
Coder avec une
Intelligence Artificielle
Voir le programme détaillé
Améliorations / Corrections
Vous avez des améliorations (ou des corrections) à proposer pour ce document : je vous remerçie par avance de m'en faire part, cela m'aide à améliorer le site.
Emplacement :
Description des améliorations :