How to save a list as numpy array in python?

Question

Is possible to construct a NumPy array from a python list?

Answer 1

you mean something like this ?

from numpy  import array
a = array( your_list )

Answer 2

First of all, I'd recommend you to go through NumPy's Quickstart tutorial, which will probably help with these basic questions.

You can directly create an array from a list as:

import numpy as np
a = np.array( [2,3,4] )

Or from a from a nested list in the same way:

import numpy as np
a = np.array( [[2,3,4], [3,4,5]] )

Answer 3

You can use numpy.asarray, for example to convert a list into an array:

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

Answer 4

I suppose, you mean converting a list into a numpy array? Then,

import numpy as np

# b is some list, then ...    
a = np.array(b).reshape(lengthDim0, lengthDim1);

gives you a as an array of list b in the shape given in reshape.

Answer 5

maybe:

import numpy as np
a=[[1,1],[2,2]]
b=np.asarray(a)
print(type(b))

output:

<class 'numpy.ndarray'>

Answer 6

You want to save it as a file?

import numpy as np

myList = [1, 2, 3]

np.array(myList).dump(open('array.npy', 'wb'))

... and then read:

myArray = np.load(open('array.npy', 'rb'))