"attributeerror: 'matrix' Object Has No Attribute 'strftime'" Error In Numpy Python

I have a matrix with (72000, 1) dimension. This matrix involves timestamps. I want to use 'strftime' as the following; strftime('%d/%m/%y'), in order to get the output something li

Solution 1:

As the error message shows you, you cannot do something like matrix.strftime . One thing you can do would be to use numpy.apply_along_axis . Example -

np.apply_along_axis((lambda x:[x[0].strftime("%d/%m/%y")]),1,M)

Demo -

In [58]: M = np.matrix([[datetime.datetime.now()]*5]).T

In [59]: M.shape
Out[59]: (5, 1)

In [60]: np.apply_along_axis((lambda x:[x[0].strftime("%d/%m/%y")]),1,M)
Out[60]:
array([['10/10/15'],
       ['10/10/15'],
       ['10/10/15'],
       ['10/10/15'],
       ['10/10/15']],
      dtype='<U8')

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For the new error you are getting -

"AttributeError: 'numpy.float64' object has no attribute 'strftime'"

This means that the objects are not datetime objects, so if they are timestamps , you can converting them to datetime first. Example -

np.apply_along_axis((lambda x:[datetime.datetime.fromtimestamp(x[0]).strftime("%d/%m/%y")]),1,M)