[Numpy-discussion] ArrayList object

[Nicolas Rougier]

Hi all,

I've coding an ArrayList object based on a regular numpy array. This objects allows to dynamically append/insert/delete/access items. I found it quite convenient since it allows to manipulate an array as if it was a list with elements of different sizes but with same underlying type (=array dtype).

# Creation from a nested list
L = ArrayList([ [0], [1,2], [3,4,5], [6,7,8,9] ])

# Creation from an array + common item size
L = ArrayList(np.ones(1000), 3)

# Empty list
L = ArrayList(dype=int)

# Creation from an array + individual item sizes
L = ArrayList(np.ones(10), 1+np.arange(4))

# Access to elements:
print L[0], L[1], L[2], L[3]
[0] [1 2] [3 4 5] [6 7 8 9]

# Operations on elements
L[:2] += 1
print L.data
[1 2 3 3 4 5 6 7 8 9]


Source code is available from: https://github.com/rougier/array-list

I wonder is there is any interest in having such object within core numpy (np.list ?) ?


Nicolas