numpy tostring() fromstring()，numpyfromstring

must specify the right dtype !!!

a
Out[54]: array([1, 2, 3])
b = a.tostring()
np.fromstring(b)
Out[52]: array([  4.94065646e-324,   9.88131292e-324,   1.48219694e-323]) #Wrong!
Out[56]: array([1, 2, 3])
type(a)
Out[57]: numpy.ndarray
type(a[0])
Out[58]: numpy.int64
np.fromstring(b, dtype=np.int64) # must use the right type!!!
Out[60]: array([1, 2, 3])

######### when read string from numpy (python3) ########
a[1] + 'haha'  ## error
str(a[1]) + 'haha'  ### correct