np.set_printoptions

set_printoptions(precision=None, threshold=None, edgeitems=None, linewidth=None, suppress=None, nanstr=None, infstr=None)

precision : int, optional，float输出的精度，即小数点后维数，默认8（ Number of digits of precision for floating point output (default 8)）

threshold : int, optional，当数组数目过大时，设置显示几个数字，其余用省略号（Total number of array elements which trigger summarization rather than full repr (default 1000).）

edgeitems : int, optional，边缘数目（Number of array items in summary at beginning and end of each dimension (default 3)）.

linewidth : int, optional，The number of characters per line for the purpose of inserting line breaks (default 75).

suppress : bool, optional，是否压缩由科学计数法表示的浮点数（Whether or not suppress printing of small floating point values using scientific notation (default False).）

nanstr : str, optional，String representation of floating point not-a-number (default nan).

infstr : str, optional，String representation of floating point infinity (default inf).

np.set_printoptions(threshold=np.nan)
设置打印时显示方式,threshold=np.nan意思是输出数组的时候完全输出，不需要省略号将中间数据省略

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

>>> np.set_printoptions(threshold=5)
>>> print np.arange(10)
[0 1 2 ..., 7 8 9]

>>> eps = np.finfo(float).eps
>>> x = np.arange(4.)
>>> x**2 - (x + eps)**2
array([ -4.9304e-32,  -4.4409e-16,   0.0000e+00,   0.0000e+00])
>>> np.set_printoptions(suppress=True)
>>> x**2 - (x + eps)**2
array([-0., -0.,  0.,  0.])