如何以正常方式而不是科学记数法强制进行ndarray演出？

Question

我正在尝试在屏幕上打印一个ndarray.但是python总是用科学记数法表示,我不喜欢.对于标量,我们可以使用

>>> print '%2.4f' %(7.47212470e-01)
0.7472

但是如何为这样的numpy.ndarray做到这一点:

[[  7.47212470e-01   3.71730070e-01   1.16736538e-01   1.22172891e-02]
 [  2.79279640e+00   1.31147152e+00   7.43946656e-02   3.08162255e-02]
 [  6.93657970e+00   3.14008688e+00   1.02851599e-01   3.96611266e-02]
 [  8.49295040e+00   3.94730094e+00   8.99398479e-02   7.60969188e-02]
 [  2.01849250e+01   8.62584092e+00   8.75722302e-02   6.17109672e-02]
 [  2.22570710e+01   1.00291292e+01   1.20918359e-01   1.07250131e-01]
 [  2.82496660e+01   1.27882133e+01   1.08438172e-01   1.58723714e-01]
 [  5.89170270e+01   2.55268510e+01   1.31990966e-01   1.61599514e-01]]

方法.astype(float)不会更改结果,而.round(4)会返回:

[[  7.47200000e-01   3.71700000e-01   1.16700000e-01   1.22000000e-02]
 [  2.79280000e+00   1.31150000e+00   7.44000000e-02   3.08000000e-02]
 [  6.93660000e+00   3.14010000e+00   1.02900000e-01   3.97000000e-02]
 [  8.49300000e+00   3.94730000e+00   8.99000000e-02   7.61000000e-02]
 [  2.01849000e+01   8.62580000e+00   8.76000000e-02   6.17000000e-02]
 [  2.22571000e+01   1.00291000e+01   1.20900000e-01   1.07300000e-01]
 [  2.82497000e+01   1.27882000e+01   1.08400000e-01   1.58700000e-01]
 [  5.89170000e+01   2.55269000e+01   1.32000000e-01   1.61600000e-01]]

我只是想要0.7472 0.3717等

Answer 1

该numpy.set_string_function函数可用于更改数组的字符串表示形式.

您还可以使用numpy.set_print_options更改默认使用的精度并以科学计数法关闭小数字的报告.

从以下示例set_print_options:

>>> np.set_printoptions(precision=4)
>>> print np.array([1.123456789])
[ 1.1235]