擅长:python、mysql、java
<pre><code>import numpy as np
import itertools
import csv
year = np.repeat((1980, 1990 , 2000, 2010), 10)
sex = np.array(['male', 'female']*20)
disease = np.repeat(('d1', 'd2', 'd3', 'd4', 'd5', 'd6', 'd7', 'd8'), 5)
draws = np.random.normal(0, 1, size=(sex.shape[0], 1000))
years=np.unique(year)
diseases=np.unique(disease)
draw_sums = dict(((y,d), draws[(year==y)&(disease==d)].sum(axis=0))
for y,d in itertools.product(years,diseases))
</code></pre>
<p>这就产生了一个dict,将每个(年、疾病)与相应的提取总和相关联。要将<code>draw_sums</code>写入<a href="http://file:///usr/share/doc/python2.6/html/library/csv.html#module-csv" rel="nofollow">csv</a>,可以执行以下操作:</p>
^{pr2}$