使用numpy.round时出现“ AttributeError：rint”

Question

我有一个像这样的numpy数组：

[[41.743617 -87.626839]
 [41.936943 -87.669838]
 [41.962665 -87.65571899999999]]

我想将数组中的数字四舍五入到小数点后两位或三位。我尝试使用numpy.around和numpy.round，但是它们都给我以下错误：

  File "/Library/Python/2.7/site-packages/numpy-1.8.0.dev_3084618_20130514-py2.7-macosx-10.8-intel.egg/numpy/core/fromnumeric.py", line 2452, in round_
    return round(decimals, out)
AttributeError: rint

我曾经numpy.around(x, decimals = 2) 和numpy.round(x,decimals=2)

难道我做错了什么？还有其他方法可以有效地对大型阵列执行此操作吗？

Answer 1

您不能对作为对象的numpy数组进行四舍五入astype，只要可以将数组安全地转换为float即可更改此值：

>>> a = np.random.rand(5).astype(np.object)
>>> a
array([0.5137250555772075, 0.4279757819721647, 0.4177118178603122,
       0.6270676923544128, 0.43733218329094947], dtype=object)

>>> np.around(a,3)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/fromnumeric.py", line 2384, in around
    return round(decimals, out)
AttributeError: rint

>>> np.around(a.astype(np.double),3)
array([ 0.514,  0.428,  0.418,  0.627,  0.437])

对于字符串，unicode，void和char类型的数组，您将收到类似的错误。