python np.c_ error"CClass object is not callabel"

Question

I'm using ipython 4.0.1 and python 3.5.1, when I call np.c_(), it shows an error

CClass object is not callable.

This is my code:

import numpy as np


rows = []
with open('ntumlone.dat') as f:
    rows = [list(map(float, L.split())) for L in f]

arr = np.array(rows)

date = np.c_(np.ones(len(arr)), arr)

What's wrong with me?

Answer 1

Try

date = np.c_[np.ones(len(arr)), arr]

Check its docs. You 'call' it with square brackets, as though you are indexing, not with (). If the distinction is too confusing stick with concatenate or one of the stack functions. I think in this use it is the same as vstack.