fill array in list with zeros

Question

I have this list:

a = [ np.array([ 1, 2]), np.array([0])]

I want to iterate:

x = np.array([t[i] for i, t in enumerate(a)])

but since np.array([0]) has only one element, it will throw an error.

So, I thought to fill the np.array([0]) with another one zero , and then

a = [ np.array([ 1,  2]), np.array([0,0])]
x = np.array([t[i] for i, t in enumerate(a)])
print(x)

[1 0]

So, I am finding the biggest length in the list:

temp = []
for i in a:
    temp.append(len(i))

themax = max(temp)

which is 2. (the np.array([1, 2]).

Now, I must somehow fill the other subelements with zeros..

Note, that I will always have the zero np.array([0]) which causes the problem.

@Jan:No, I will have zeros in the list and i have to keep them. — George
– George, Commented Mar 7, 2017 at 9:02

jotasi · Accepted Answer · 2017-03-07 09:11:28Z

1

The easiest way would be to change your list comprehension to give a zero instead of an array element in the case of an array being too small:

x = np.asarray([(t[i] if i < t.shape[0] else 0.) for i, t in enumerate(a)])

This is more efficient as you don't have to expand all arrays with zeros.

answered Mar 7, 2017 at 9:11

jotasi

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