numpy的random模块

最新推荐文章于 2022-06-17 21:09:30 发布

charlesqinjiaqi

最新推荐文章于 2022-06-17 21:09:30 发布

阅读量1.9k

点赞数

分类专栏： numpy-python-2-7 文章标签： numpy random

numpy-python-2-7 专栏收录该内容

1 篇文章

订阅专栏

本文介绍了NumPy中random模块的功能，包括生成不同类型的随机数、随机样本及各种统计分布的样本等。通过丰富的实例展示了如何使用这些函数进行随机数据生成。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

id="iframeu2910326_0" src="http://pos.baidu.com/ycam?rdid=2910326&dc=3&di=u2910326&dri=0&dis=0&dai=1&ps=158x817&dcb=___adblockplus&dtm=HTML_POST&dvi=0.0&dci=-1&dpt=none&tsr=0&tpr=1500859826702&ti=numpy%E7%9A%84random%E6%A8%A1%E5%9D%97&ari=2&dbv=2&drs=1&pcs=1268x630&pss=1269x2159&cfv=0&cpl=25&chi=1&cce=true&cec=UTF-8&tlm=1500859826&rw=630&ltu=http%3A%2F%2Fwww.mamicode.com%2Finfo-detail-507676.html&ecd=1&uc=1920x1040&pis=-1x-1&sr=1920x1080&tcn=1500859827&qn=7b5e8407159a05f6&tt=1500859826643.65.96.99" width="336" height="280" align="center,center" vspace="0" hspace="0" scrolling="no">

numpy的random模块

时间： 2015-03-10 06:46:22 阅读： 43938 评论： 0 收藏： 1 [点我收藏+]

标签：

【说明】

翻译自官网的文档。

随机抽样 (`numpy.random`)

简单的随机数据

rand(d0, d1, …, dn)

随机值

>>> np.random.rand(3,2)
array([[ 0.14022471,  0.96360618],  #random
       [ 0.37601032,  0.25528411],  #random
       [ 0.49313049,  0.94909878]]) #random

randn(d0, d1, …, dn)

返回一个样本，具有标准正态分布。

Notes

For random samples from $技术分享$ , use:

sigma * np.random.randn(...) + mu

Examples

>>> np.random.randn()
2.1923875335537315 #random

Two-by-four array of samples from N(3, 6.25):

>>> 2.5 * np.random.randn(2, 4) + 3
array([[-4.49401501,  4.00950034, -1.81814867,  7.29718677],  #random
       [ 0.39924804,  4.68456316,  4.99394529,  4.84057254]]) #random

randint(low[, high, size])

返回随机的整数，位于半开区间 [low, high)。

>>> np.random.randint(2, size=10)
array([1, 0, 0, 0, 1, 1, 0, 0, 1, 0])
>>> np.random.randint(1, size=10)
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0])

Generate a 2 x 4 array of ints between 0 and 4, inclusive:

>>> np.random.randint(5, size=(2, 4))
array([[4, 0, 2, 1],
       [3, 2, 2, 0]])

random_integers(low[, high, size])

返回随机的整数，位于闭区间 [low, high]。

Notes

To sample from N evenly spaced floating-point numbers between a and b, use:

a + (b - a) * (np.random.random_integers(N) - 1) / (N - 1.)

Examples

>>> np.random.random_integers(5)
4
>>> type(np.random.random_integers(5))
<type ‘int‘>
>>> np.random.random_integers(5, size=(3.,2.))
array([[5, 4],
       [3, 3],
       [4, 5]])

Choose five random numbers from the set of five evenly-spaced numbers between 0 and 2.5, inclusive (i.e., from the set $技术分享$ ):

>>> 2.5 * (np.random.random_integers(5, size=(5,)) - 1) / 4.
array([ 0.625,  1.25 ,  0.625,  0.625,  2.5  ])

Roll two six sided dice 1000 times and sum the results:

>>> d1 = np.random.random_integers(1, 6, 1000)
>>> d2 = np.random.random_integers(1, 6, 1000)
>>> dsums = d1 + d2

Display results as a histogram:

>>> import matplotlib.pyplot as plt
>>> count, bins, ignored = plt.hist(dsums, 11, normed=True)
>>> plt.show()

random_sample([size])

返回随机的浮点数，在半开区间 [0.0, 1.0)。

To sample $技术分享$ multiply the output of random_sample by (b-a) and add a:

(b - a) * random_sample() + a

Examples

>>> np.random.random_sample()
0.47108547995356098
>>> type(np.random.random_sample())
<type ‘float‘>
>>> np.random.random_sample((5,))
array([ 0.30220482,  0.86820401,  0.1654503 ,  0.11659149,  0.54323428])

Three-by-two array of random numbers from [-5, 0):

>>> 5 * np.random.random_sample((3, 2)) - 5
array([[-3.99149989, -0.52338984],
       [-2.99091858, -0.79479508],
       [-1.23204345, -1.75224494]])

random([size])

返回随机的浮点数，在半开区间 [0.0, 1.0)。

（官网例子与random_sample完全一样）

ranf([size])

返回随机的浮点数，在半开区间 [0.0, 1.0)。

（官网例子与random_sample完全一样）

sample([size])

返回随机的浮点数，在半开区间 [0.0, 1.0)。

（官网例子与random_sample完全一样）

choice(a[, size, replace, p])

生成一个随机样本，从一个给定的一维数组

Examples

Generate a uniform random sample from np.arange(5) of size 3:

>>> np.random.choice(5, 3)
array([0, 3, 4])
>>> #This is equivalent to np.random.randint(0,5,3)

Generate a non-uniform random sample from np.arange(5) of size 3:

>>> np.random.choice(5, 3, p=[0.1, 0, 0.3, 0.6, 0])
array([3, 3, 0])

Generate a uniform random sample from np.arange(5) of size 3 without replacement:

>>> np.random.choice(5, 3, replace=False)
array([3,1,0])
>>> #This is equivalent to np.random.permutation(np.arange(5))[:3]

Generate a non-uniform random sample from np.arange(5) of size 3 without replacement:

>>> np.random.choice(5, 3, replace=False, p=[0.1, 0, 0.3, 0.6, 0])
array([2, 3, 0])

Any of the above can be repeated with an arbitrary array-like instead of just integers. For instance:

>>> aa_milne_arr = [‘pooh‘, ‘rabbit‘, ‘piglet‘, ‘Christopher‘]
>>> np.random.choice(aa_milne_arr, 5, p=[0.5, 0.1, 0.1, 0.3])
array([‘pooh‘, ‘pooh‘, ‘pooh‘, ‘Christopher‘, ‘piglet‘],
      dtype=‘|S11‘)

bytes(length)

返回随机字节。

>>> np.random.bytes(10)
‘ eh\x85\x022SZ\xbf\xa4‘ #random

排列

shuffle(x)

现场修改序列，改变自身内容。（类似洗牌，打乱顺序）

>>> arr = np.arange(10)
>>> np.random.shuffle(arr)
>>> arr
[1 7 5 2 9 4 3 6 0 8]

This function only shuffles the array along the first index of a multi-dimensional array:

>>> arr = np.arange(9).reshape((3, 3))
>>> np.random.shuffle(arr)
>>> arr
array([[3, 4, 5],
       [6, 7, 8],
       [0, 1, 2]])

permutation(x)

返回一个随机排列

>>> np.random.permutation(10)
array([1, 7, 4, 3, 0, 9, 2, 5, 8, 6])

>>> np.random.permutation([1, 4, 9, 12, 15])
array([15,  1,  9,  4, 12])

>>> arr = np.arange(9).reshape((3, 3))
>>> np.random.permutation(arr)
array([[6, 7, 8],
       [0, 1, 2],
       [3, 4, 5]])

分布

`beta`(a, b[, size])	贝塔分布样本，在 `[0, 1]`内。
`binomial`(n, p[, size])	二项分布的样本。
`chisquare`(df[, size])	卡方分布样本。
`dirichlet`(alpha[, size])	狄利克雷分布样本。
`exponential`([scale, size])	指数分布
`f`(dfnum, dfden[, size])	F分布样本。
`gamma`(shape[, scale, size])	伽马分布
`geometric`(p[, size])	几何分布
`gumbel`([loc, scale, size])	耿贝尔分布。
`hypergeometric`(ngood, nbad, nsample[, size])	超几何分布样本。
`laplace`([loc, scale, size])	拉普拉斯或双指数分布样本
`logistic`([loc, scale, size])	Logistic分布样本
`lognormal`([mean, sigma, size])	对数正态分布
`logseries`(p[, size])	对数级数分布。
`multinomial`(n, pvals[, size])	多项分布
`multivariate_normal`(mean, cov[, size])	多元正态分布。 >>> mean = [0,0] >>> cov = [[1,0],[0,100]] # diagonal covariance, points lie on x or y-axis >>> import matplotlib.pyplot as plt >>> x, y = np.random.multivariate_normal(mean, cov, 5000).T >>> plt.plot(x, y, ‘x‘); plt.axis(‘equal‘); plt.show()
`negative_binomial`(n, p[, size])	负二项分布
`noncentral_chisquare`(df, nonc[, size])	非中心卡方分布
`noncentral_f`(dfnum, dfden, nonc[, size])	非中心F分布
`normal`([loc, scale, size])	正态(高斯)分布 Notes The probability density for the Gaussian distribution is $技术分享$ where $技术分享$ is the mean and $技术分享$ the standard deviation. The square of the standard deviation, $技术分享$ , is called the variance. The function has its peak at the mean, and its “spread” increases with the standard deviation (the function reaches 0.607 times its maximum at $技术分享$ and $技术分享$ [R217]). Examples Draw samples from the distribution: >>> mu, sigma = 0, 0.1 # mean and standard deviation >>> s = np.random.normal(mu, sigma, 1000) Verify the mean and the variance: >>> abs(mu - np.mean(s)) < 0.01 True >>> abs(sigma - np.std(s, ddof=1)) < 0.01 True Display the histogram of the samples, along with the probability density function: >>> import matplotlib.pyplot as plt >>> count, bins, ignored = plt.hist(s, 30, normed=True) >>> plt.plot(bins, 1/(sigma * np.sqrt(2 * np.pi)) * ... np.exp( - (bins - mu)*2 / (2 sigma**2) ), ... linewidth=2, color=‘r‘) >>> plt.show()
`pareto`(a[, size])	帕累托（Lomax）分布
`poisson`([lam, size])	泊松分布
`power`(a[, size])	Draws samples in [0, 1] from a power distribution with positive exponent a - 1.
`rayleigh`([scale, size])	Rayleigh 分布
`standard_cauchy`([size])	标准柯西分布
`standard_exponential`([size])	标准的指数分布
`standard_gamma`(shape[, size])	标准伽马分布
`standard_normal`([size])	标准正态分布 (mean=0, stdev=1).
`standard_t`(df[, size])	Standard Student’s t distribution with df degrees of freedom.
`triangular`(left, mode, right[, size])	三角形分布
`uniform`([low, high, size])	均匀分布
`vonmises`(mu, kappa[, size])	von Mises分布
`wald`(mean, scale[, size])	瓦尔德（逆高斯）分布
`weibull`(a[, size])	Weibull 分布
`zipf`(a[, size])	齐普夫分布

随机数生成器

RandomState

Container for the Mersenne Twister pseudo-random number generator.

seed([seed])

Seed the generator.

get_state()

Return a tuple representing the internal state of the generator.

set_state(state)

Set the internal state of the generator from a tuple.

numpy的random模块

标签：

踩

( 3)

( 30)

id="iframeu2910327_0" src="http://pos.baidu.com/ycam?rdid=2910327&dc=3&di=u2910327&dri=0&dis=0&dai=2&ps=10654x817&dcb=___adblockplus&dtm=HTML_POST&dvi=0.0&dci=-1&dpt=none&tsr=0&tpr=1500859826702&ti=numpy%E7%9A%84random%E6%A8%A1%E5%9D%97&ari=2&dbv=2&drs=1&pcs=1268x630&pss=1269x10938&cfv=0&cpl=25&chi=1&cce=true&cec=UTF-8&tlm=1500859826&rw=630&ltu=http%3A%2F%2Fwww.mamicode.com%2Finfo-detail-507676.html&ecd=1&uc=1920x1040&pis=-1x-1&sr=1920x1080&tcn=1500859827&qn=33fe853a2f87dc0e&tt=1500859826643.280.281.282" width="336" height="280" align="center,center" vspace="0" hspace="0" scrolling="no">

评论一句话评论（0）

                        <div id="commentlistend" name="commentlistend" class="divtextaligncenter margintop20">
                            <span id="lblpage">共<span class="pagecolorc">0</span>条&nbsp;&nbsp;</span>
                        </div>
                    </div>
                    <div class="margintop20">
                        <form method="post" action="/ajaxjs/info_detail_commentadd.aspx">
                        <div class="divtextalignleft paddingtop20">
                            <div id="commenthf" class="divbackgroundcolor1">
                            </div>
                            <div>
                                <textarea name="tbcommentcontent" id="tbcommentcontent" class="tb" style="width: 680px;
                                    height: 120px;"></textarea>
                            </div>
                        </div>
                        <div class="divtextalignright paddingtop10 ">
                            <span id="addCommentTishi" class="colorboldHong">登录后才能评论！</span>
                            <span id="loginno"><input type="button" class="mbtn1" value="登录" onclick="location.href='http://member.mamicode.com/login.aspx?returnUrl='+document.URL.replace(new RegExp('&amp;', 'g'), '(_)')"></span>
                        </div>
                        </form>
                    </div>
                </div>
            </div>
            <script type="text/javascript">                    mamicode_adload('content_bottom');</script><div class="margintop20">    <script type="text/javascript">        /*mamicode-bottom-680x250*/        var cpro_id = "u2811621";    </script>    <script type="text/javascript" src="http://cpro.baidustatic.com/cpro/ui/c.js"></script><div id="BAIDU_SSP__wrapper_u2811621_0"><iframe id="iframeu2811621_0" src="http://pos.baidu.com/ycam?rdid=2811621&amp;dc=3&amp;di=u2811621&amp;dri=0&amp;dis=0&amp;dai=3&amp;ps=11270x126&amp;dcb=___adblockplus&amp;dtm=HTML_POST&amp;dvi=0.0&amp;dci=-1&amp;dpt=none&amp;tsr=0&amp;tpr=1500859826702&amp;ti=numpy%E7%9A%84random%E6%A8%A1%E5%9D%97&amp;ari=2&amp;dbv=2&amp;drs=1&amp;pcs=1268x630&amp;pss=1269x11271&amp;cfv=0&amp;cpl=25&amp;chi=1&amp;cce=true&amp;cec=UTF-8&amp;tlm=1500859826&amp;rw=630&amp;ltu=http%3A%2F%2Fwww.mamicode.com%2Finfo-detail-507676.html&amp;ecd=1&amp;uc=1920x1040&amp;pis=-1x-1&amp;sr=1920x1080&amp;tcn=1500859827&amp;qn=22368b720b4c12ee&amp;tt=1500859826643.314.314.314" width="680" height="250" align="center,center" vspace="0" hspace="0" marginwidth="0" marginheight="0" scrolling="no" frameborder="0" style="border:0;vertical-align:bottom;margin:0;width:680px;height:250px" allowtransparency="true"></iframe></div></div><div class="divtextaligncenter margintop20">    <script type="text/javascript">        /*mamicode-infodetail-title-top-680x250*/        var cpro_id = "u2860054";    </script>    <script src="http://cpro.baidustatic.com/cpro/ui/c.js" type="text/javascript"></script><div id="BAIDU_SSP__wrapper_u2860054_0"><iframe id="iframeu2860054_0" src="http://pos.baidu.com/ycam?rdid=2860054&amp;dc=3&amp;di=u2860054&amp;dri=0&amp;dis=0&amp;dai=4&amp;ps=11565x126&amp;dcb=___adblockplus&amp;dtm=HTML_POST&amp;dvi=0.0&amp;dci=-1&amp;dpt=none&amp;tsr=0&amp;tpr=1500859826702&amp;ti=numpy%E7%9A%84random%E6%A8%A1%E5%9D%97&amp;ari=2&amp;dbv=2&amp;drs=1&amp;pcs=1268x630&amp;pss=1269x11565&amp;cfv=0&amp;cpl=25&amp;chi=1&amp;cce=true&amp;cec=UTF-8&amp;tlm=1500859826&amp;rw=630&amp;ltu=http%3A%2F%2Fwww.mamicode.com%2Finfo-detail-507676.html&amp;ecd=1&amp;uc=1920x1040&amp;pis=-1x-1&amp;sr=1920x1080&amp;tcn=1500859827&amp;qn=13f461ea45b9a4ea&amp;tt=1500859826643.330.330.331" width="680" height="250" align="center,center" vspace="0" hspace="0" marginwidth="0" marginheight="0" scrolling="no" frameborder="0" style="border:0;vertical-align:bottom;margin:0;width:680px;height:250px" allowtransparency="true"></iframe></div></div>
        </div>
    </div>
    <div class="width30bi divfloatright">

        <div class="paddingbottom20">
<script type="text/javascript">        (function () { document.write(unescape('%3Cdiv id="bdcs"%3E%3C/div%3E')); var bdcs = document.createElement('script'); bdcs.type = 'text/javascript'; bdcs.async = true; bdcs.src = 'http://znsv.baidu.com/customer_search/api/js?sid=7490613033886828738' + '&plate_url=' + encodeURIComponent(window.location.href) + '&t=' + Math.ceil(new Date() / 3600000); var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(bdcs, s); })();</script><div id="bdcs"><div class="bdcs-container"><meta http-equiv="x-ua-compatible" content="IE=9">   <!-- 嵌入式 -->  <div class="bdcs-main bdcs-clearfix" id="default-searchbox">      <div class="bdcs-search bdcs-clearfix" id="bdcs-search-inline">          <form action="http://zhannei.baidu.com/cse/search" method="get" target="_blank" class="bdcs-search-form" autocomplete="off" id="bdcs-search-form">              <input type="hidden" name="s" value="7490613033886828738">              <input type="hidden" name="entry" value="1">                                                                        <input type="text" name="q" class="bdcs-search-form-input" id="bdcs-search-form-input" placeholder="请输入关键词" style="height: 34px; line-height: 34px;">              <input type="submit" class="bdcs-search-form-submit " id="bdcs-search-form-submit" value="搜索">                       </form>      </div>                  </div>                           </div></div>

        <script type="text/javascript">                mamicode_adload('right_top');</script><div class="paddingbottom10">    <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>    <!-- 1-mamicode-right-300x600 -->    <ins class="adsbygoogle" style="display: inline-block; width: 300px; height: 600px" data-ad-client="ca-pub-8616102841876629" data-ad-slot="8947049888" data-adsbygoogle-status="done"><ins id="aswift_3_expand" style="display:inline-table;border:none;height:600px;margin:0;padding:0;position:relative;visibility:visible;width:300px;background-color:transparent"><ins id="aswift_3_anchor" style="display:block;border:none;height:600px;margin:0;padding:0;position:relative;visibility:visible;width:300px;background-color:transparent"><iframe width="300" height="600" frameborder="0" marginwidth="0" marginheight="0" vspace="0" hspace="0" allowtransparency="true" scrolling="no" allowfullscreen="true" onload="var i=this.id,s=window.google_iframe_oncopy,H=s&amp;&amp;s.handlers,h=H&amp;&amp;H[i],w=this.contentWindow,d;try{d=w.document}catch(e){}if(h&amp;&amp;d&amp;&amp;(!d.body||!d.body.firstChild)){if(h.call){setTimeout(h,0)}else if(h.match){try{h=s.upd(h,i)}catch(e){}w.location.replace(h)}}" id="aswift_3" name="aswift_3" style="left:0;position:absolute;top:0;width:300px;height:600px;"></iframe></ins></ins></ins>    <script>        (adsbygoogle = window.adsbygoogle || []).push({});    </script></div>

分享档案

周排行

        <script type="text/javascript">                mamicode_adload('right_bottom');</script><div id="xuanting" class="width300px margintop5" style="left: 834px; top: 1px; z-index: 1000; position: fixed;">    <script async="" src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>    <!-- mamicode-right-xuanting-300x600 -->    <ins class="adsbygoogle" style="display: inline-block; width: 300px; height: 0px;" data-ad-client="ca-pub-8616102841876629" data-ad-slot="4406515082" data-adsbygoogle-status="done"><ins id="aswift_4_expand" style="display: inline-table; border: none; height: 0px; margin: 0px; padding: 0px; position: relative; visibility: visible; width: 300px; background-color: transparent;"><ins id="aswift_4_anchor" style="display: block; border: none; height: 0px; margin: 0px; padding: 0px; position: relative; visibility: visible; width: 300px; overflow: hidden; transition: opacity 1s cubic-bezier(0.4, 0, 1, 1), width 0.2s cubic-bezier(0.4, 0, 1, 1) 0.3s, height 0.5s cubic-bezier(0.4, 0, 1, 1); opacity: 0; background-color: transparent;"><iframe width="300" height="600" frameborder="0" marginwidth="0" marginheight="0" vspace="0" hspace="0" allowtransparency="true" scrolling="no" allowfullscreen="true" onload="var i=this.id,s=window.google_iframe_oncopy,H=s&amp;&amp;s.handlers,h=H&amp;&amp;H[i],w=this.contentWindow,d;try{d=w.document}catch(e){}if(h&amp;&amp;d&amp;&amp;(!d.body||!d.body.firstChild)){if(h.call){setTimeout(h,0)}else if(h.match){try{h=s.upd(h,i)}catch(e){}w.location.replace(h)}}" id="aswift_4" name="aswift_4" style="left:0;position:absolute;top:0;width:300px;height:600px;"></iframe></ins></ins></ins>    <script>        (adsbygoogle = window.adsbygoogle || []).push({});    </script></div>
    </div>
    <div class="divfloatclear">
    </div>
</div>