Python 3 Random 모듈 코드 상세 설명
random()방법 은 무 작위 로 생 성 된 실 수 를 되 돌려 줍 니 다.[0,1)범위 내 에 있 습 니 다.
import random
help(random)
FUNCTIONS
betavariate(alpha, beta) method of Random instance #
Beta distribution. # β
Conditions on the parameters are alpha > 0 and beta > 0. # 0 alpha beta
Returned values range between 0 and 1. # 0 -1 , !
a = random.betavariate(999999, 99999999999999999) # :9.995974671839104e-12 :1.0006927848540756e-11
(Beta Distribution) , 。
, , Β , (0,1) 。
choice(seq) method of Random instance
Choose a random element from a non-empty sequence. # ,
Python 6 , 、 、 、Unicode 、buffer xrange 。
choices(population, weights=None, *, cum_weights=None, k=1) method of Random instance #
Return a k sized list of population elements chosen with replacement. # chosen with replacement( , ) k
If the relative weights or cumulative weights are not specified, # ,
the selections are made with equal probability. # 。
population k ( )。 。
:
print(random.choices(['red', 'black', 'green'], [18, 18, 2], k=6) ) # 18 red,18 black,2 green, 6
trial = lambda: random.choices('HT', cum_weights=(0.60, 1.00), k=7).count('H') >= 5 # H 0.6,T 0.4
print(sum(trial() for i in range(10000)) / 10000)
trial2 = lambda : 2500 <= sorted(random.choices(range(10000), k=5))[2] < 7500
print(sum(trial2() for i in range(10000)) / 10000 )
from statistics import mean
data = 1, 2, 4, 4, 10
means = sorted(mean(random.choices(data, k=5)) for i in range(20)) # mean
print(f'The sample mean of {mean(data):.1f} has a 90% confidence '
f'interval from {means[1]:.1f} to {means[-2]:.1f}') # f
# :
# The sample mean of 4.2 has a 90% confidence interval from 2.4 to 6.6
# The sample mean of 4.2 has a 90% confidence interval from 2.6 to 7.2
# The sample mean of 4.2 has a 90% confidence interval from 2.0 to 7.0
expovariate(lambd) method of Random instance #
Exponential distribution. #
lambd is 1.0 divided by the desired mean. It should be
nonzero. (The parameter would be called "lambda", but that is
a reserved word in Python.) Returned values range from 0 to
positive infinity if lambd is positive, and from negative
infinity to 0 if lambd is negative.
λ(lambd) 1 , 。( lambda, python )
0 ( λ ), 0 , ( λ )
gammavariate(alpha, beta) method of Random instance #
Gamma distribution. Not the gamma function! # . gamma
Conditions on the parameters are alpha > 0 and beta > 0. # 0
The probability distribution function is: # :
x ** (alpha - 1) * math.exp(-x / beta)
pdf(x) = --------------------------------------
math.gamma(alpha) * beta ** alpha
gauss(mu, sigma) method of Random instance #
Gaussian distribution. # ,
mu is the mean, and sigma is the standard deviation. This is
slightly faster than the normalvariate() function.
Not thread-safe without a lock around calls.
# mu ,sigma , normalvariate()
# , 。
# ,mu sigma,
getrandbits(...) method of Random instance #
getrandbits(k) -> x. Generates an int with k random bits. # k ( )。 ( ), 。
getstate() method of Random instance #
Return internal state; can be passed to setstate() later. # . setstate() .
lognormvariate(mu, sigma) method of Random instance #
Log normal distribution.
(logarithmic normal distribution) , 。
, 。 , 。
If you take the natural logarithm of this distribution, you'll get a
normal distribution with mean mu and standard deviation sigma.
mu can have any value, and sigma must be greater than zero.
# , mu, sigma 。
# mu ,sigma 0
normalvariate(mu, sigma) method of Random instance #
Normal distribution. # ,
mu is the mean, and sigma is the standard deviation. # mu ,sigma
paretovariate(alpha) method of Random instance #
Pareto distribution. alpha is the shape parameter. # ; alpha
# (Pareto distribution) ・ , ,
# , 。 20% 80% , ・
# (80/20 ), 。
randint(a, b) method of Random instance #
Return random integer in range [a, b], including both end points. # a b , a b
# , a, b , ,a b 。
random(...) method of Random instance #
random() -> x in the interval [0, 1). # , 0-1 , 0, 1
randrange(start, stop=None, step=1, _int=<class 'int'>) method of Random instance #
Choose a random item from range(start, stop[, step]). #
This fixes the problem with randint() which includes the # randint()
endpoint; in Python this is usually not what you want. # randint()
,start stop
sample(population, k) method of Random instance #
Chooses k unique random elements from a population sequence or set. # population k
Returns a new list containing elements from the population while # , 。
leaving the original population unchanged. The resulting list is
in selection order so that all sub-slices will also be valid random # 。 , 。
samples. This allows raffle winners (the sample) to be partitioned # ( )
into grand prize and second place winners (the subslices).
Members of the population need not be hashable or unique. If the # population 。
population contains repeats, then each occurrence is a possible # population ,
selection in the sample.
To choose a sample in a range of integers, use range as an argument # , 。
This is especially fast and space efficient for sampling from a #
large population: sample(range(10000000), 60) # :sample(range(10000000), 60)
seed(a=None, version=2) method of Random instance #
Initialize internal state from hashable object. #
None or no argument seeds from current time or from an operating # None , seeds
system specific randomness source if available. # ( )
If *a* is an int, all bits are used. # a , bits
For version 2 (the default), all of the bits are used if *a* is a str, # version 2( ), a ,bytes bytearray, bits
bytes, or bytearray. For version 1 (provided for reproducing random # version 1 ( python )
sequences from older versions of Python), the algorithm for str and # str,bytes 。
bytes generates a narrower range of seeds.
setstate(state) method of Random instance #
Restore internal state from object returned by getstate(). # getstate() 。
shuffle(x, random=None) method of Random instance #
Shuffle list x in place, and return None. # x None x
Optional argument random is a 0-argument function returning a # 0-1
random float in [0.0, 1.0); if it is the default None, the # None, random.random
standard random.random will be used.
, , 。
triangular(low=0.0, high=1.0, mode=None) method of Random instance #
Triangular distribution. # (triangular distribution),
Continuous distribution bounded by given lower and upper limits, # low、 high、 。
and having a given mode value in-between.
http://en.wikipedia.org/wiki/Triangular_distribution
uniform(a, b) method of Random instance #
Get a random number in the range [a, b) or [a, b] depending on rounding. # a b , a,b b
a b , , b math.ceil
vonmisesvariate(mu, kappa) method of Random instance #
Circular data distribution. # ・
mu is the mean angle, expressed in radians between 0 and 2*pi, and
kappa is the concentration parameter, which must be greater than or
equal to zero. If kappa is equal to zero, this distribution reduces
to a uniform random angle over the range 0 to 2*pi.
# mu , 0-2*pi ,kappa , 0。
# kappa 0, , κ , , 0-2*pi
weibullvariate(alpha, beta) method of Random instance
Weibull distribution. #
alpha is the scale parameter and beta is the shape parameter. # λ>0 (scale parameter),k>0 (shape parameter)
# alpha ,beta
(Weibull distribution), , 。
: , 。 ,
。
총결산이상 은 Python 3 Random 모듈 코드 에 대한 상세 한 내용 입 니 다.여러분 께 도움 이 되 기 를 바 랍 니 다.관심 이 있 는 친 구 는 본 사이트 의 다른 관련 주 제 를 계속 참고 할 수 있 습 니 다.부족 한 점 이 있 으 면 댓 글로 지적 해 주 십시오.본 사이트 에 대한 여러분 의 지지 에 감 사 드 립 니 다!
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