Best way to initialize and fill an numpy array?

Question

I want to initialize and fill a numpy array. What is the best way?

This works as I expect:

>>> import numpy as np
>>>          


        

Answer 1

I find this easy to remember:

numpy.array([numpy.nan]*3)

Out of curiosity, I timed it, and both @JoshAdel's answer and @shx2's answer are far faster than mine with large arrays.

In [34]: %timeit -n10000 numpy.array([numpy.nan]*10000)
10000 loops, best of 3: 273 µs per loop

In [35]: %timeit -n10000 numpy.empty(10000)* numpy.nan
10000 loops, best of 3: 6.5 µs per loop

In [36]: %timeit -n10000 numpy.full(10000, numpy.nan)
10000 loops, best of 3: 5.42 µs per loop