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我是Python新手,现在只是阅读教程。python中的numpy reduceat()是什么意思?
我很困惑reduceat()
函数。
我看到的例子:
np.add.reduceat([0,1,2,3,4,5,6,7],[0,4,1,5,2,6,3,7])[::2]
和结果是:
array([ 6, 10, 14, 18])
它是如何出来的?有人能为我解释吗?
我是Python新手,现在只是阅读教程。python中的numpy reduceat()是什么意思?
我很困惑reduceat()
函数。
我看到的例子:
np.add.reduceat([0,1,2,3,4,5,6,7],[0,4,1,5,2,6,3,7])[::2]
和结果是:
array([ 6, 10, 14, 18])
它是如何出来的?有人能为我解释吗?
它有点像一个滚动申请,请参阅:
In [59]:
np.add.reduceat([0,1,2,3,4,5,6,7],[0,4])
Out[59]:
array([ 6, 22])
In [65]:
np.add.reduceat([0,1,2,3,4,5,6,7],[4,1])
Out[65]:
array([ 4, 28])
In [66]:
np.add.reduceat([0,1,2,3,4,5,6,7],[1,5])
Out[66]:
array([10, 18])
In [64]:
np.add.reduceat([0,1,2,3,4,5,6,7],[5,2])
Out[64]:
array([ 5, 27])
In [61]:
np.add.reduceat([0,1,2,3,4,5,6,7],[2,6])
Out[61]:
array([14, 13])
In [67]:
np.add.reduceat([0,1,2,3,4,5,6,7],[6,3])
Out[67]:
array([ 6, 25])
In [62]:
np.add.reduceat([0,1,2,3,4,5,6,7],[3,7])
Out[62]:
array([18, 7])
如果你只想第一个值,你可以得到它只是一次完成:
In [63]:
np.add.reduceat([0,1,2,3,4,5,6,7],[0,4,1,5,2,6,3,7])
Out[63]:
array([ 6, 4, 10, 5, 14, 6, 18, 7])
有你读文档? –
http://docs.scipy.org/doc/numpy-1.6.0/reference/generated/numpy.ufunc.reduceat.html –
其实我看过了,但不明白... – xirururu