mirror of
https://github.com/python/cpython.git
synced 2024-12-01 13:55:45 +08:00
merge
This commit is contained in:
commit
c34e8604c8
@ -49,8 +49,21 @@ from sources provided by the operating system.
|
||||
security purposes. For security or cryptographic uses, see the
|
||||
:mod:`secrets` module.
|
||||
|
||||
.. seealso::
|
||||
|
||||
Bookkeeping functions:
|
||||
M. Matsumoto and T. Nishimura, "Mersenne Twister: A 623-dimensionally
|
||||
equidistributed uniform pseudorandom number generator", ACM Transactions on
|
||||
Modeling and Computer Simulation Vol. 8, No. 1, January pp.3-30 1998.
|
||||
|
||||
|
||||
`Complementary-Multiply-with-Carry recipe
|
||||
<https://code.activestate.com/recipes/576707/>`_ for a compatible alternative
|
||||
random number generator with a long period and comparatively simple update
|
||||
operations.
|
||||
|
||||
|
||||
Bookkeeping functions
|
||||
---------------------
|
||||
|
||||
.. function:: seed(a=None, version=2)
|
||||
|
||||
@ -94,7 +107,8 @@ Bookkeeping functions:
|
||||
:meth:`randrange` to handle arbitrarily large ranges.
|
||||
|
||||
|
||||
Functions for integers:
|
||||
Functions for integers
|
||||
----------------------
|
||||
|
||||
.. function:: randrange(stop)
|
||||
randrange(start, stop[, step])
|
||||
@ -117,7 +131,8 @@ Functions for integers:
|
||||
``randrange(a, b+1)``.
|
||||
|
||||
|
||||
Functions for sequences:
|
||||
Functions for sequences
|
||||
-----------------------
|
||||
|
||||
.. function:: choice(seq)
|
||||
|
||||
@ -188,6 +203,9 @@ Functions for sequences:
|
||||
If the sample size is larger than the population size, a :exc:`ValueError`
|
||||
is raised.
|
||||
|
||||
Real-valued distributions
|
||||
-------------------------
|
||||
|
||||
The following functions generate specific real-valued distributions. Function
|
||||
parameters are named after the corresponding variables in the distribution's
|
||||
equation, as used in common mathematical practice; most of these equations can
|
||||
@ -282,7 +300,8 @@ be found in any statistics text.
|
||||
parameter.
|
||||
|
||||
|
||||
Alternative Generator:
|
||||
Alternative Generator
|
||||
---------------------
|
||||
|
||||
.. class:: SystemRandom([seed])
|
||||
|
||||
@ -294,19 +313,6 @@ Alternative Generator:
|
||||
:exc:`NotImplementedError` if called.
|
||||
|
||||
|
||||
.. seealso::
|
||||
|
||||
M. Matsumoto and T. Nishimura, "Mersenne Twister: A 623-dimensionally
|
||||
equidistributed uniform pseudorandom number generator", ACM Transactions on
|
||||
Modeling and Computer Simulation Vol. 8, No. 1, January pp.3-30 1998.
|
||||
|
||||
|
||||
`Complementary-Multiply-with-Carry recipe
|
||||
<https://code.activestate.com/recipes/576707/>`_ for a compatible alternative
|
||||
random number generator with a long period and comparatively simple update
|
||||
operations.
|
||||
|
||||
|
||||
Notes on Reproducibility
|
||||
------------------------
|
||||
|
||||
@ -333,13 +339,13 @@ Basic examples::
|
||||
>>> random() # Random float: 0.0 <= x < 1.0
|
||||
0.37444887175646646
|
||||
|
||||
>>> uniform(2, 10) # Random float: 2.0 <= x < 10.0
|
||||
>>> uniform(2.5, 10.0) # Random float: 2.5 <= x < 10.0
|
||||
3.1800146073117523
|
||||
|
||||
>>> expovariate(1/5) # Interval between arrivals averaging 5 seconds
|
||||
>>> expovariate(1 / 5) # Interval between arrivals averaging 5 seconds
|
||||
5.148957571865031
|
||||
|
||||
>>> randrange(10) # Integer from 0 to 9
|
||||
>>> randrange(10) # Integer from 0 to 9 inclusive
|
||||
7
|
||||
|
||||
>>> randrange(0, 101, 2) # Even integer from 0 to 100 inclusive
|
||||
@ -362,17 +368,16 @@ Simulations::
|
||||
>>> choices(['red', 'black', 'green'], [18, 18, 2], k=6)
|
||||
['red', 'green', 'black', 'black', 'red', 'black']
|
||||
|
||||
# Deal 20 cards without replacement from a deck of 52
|
||||
# playing cards and determine the proportion of cards
|
||||
# with a ten-value (i.e. a ten, jack, queen, or king).
|
||||
# Deal 20 cards without replacement from a deck of 52 playing cards
|
||||
# and determine the proportion of cards with a ten-value (i.e. a ten,
|
||||
# jack, queen, or king).
|
||||
>>> deck = collections.Counter(tens=16, low_cards=36)
|
||||
>>> seen = sample(list(deck.elements()), k=20)
|
||||
>>> print(seen.count('tens') / 20)
|
||||
0.15
|
||||
|
||||
# Estimate the probability of getting 5 or more heads
|
||||
# from 7 spins of a biased coin that settles on heads
|
||||
# 60% of the time.
|
||||
# Estimate the probability of getting 5 or more heads from 7 spins
|
||||
# of a biased coin that settles on heads 60% of the time.
|
||||
>>> n = 10000
|
||||
>>> cw = [0.60, 1.00]
|
||||
>>> sum(choices('HT', cum_weights=cw, k=7).count('H') >= 5 for i in range(n)) / n
|
||||
|
Loading…
Reference in New Issue
Block a user