Indexing a nested list in python
list, multidimensional-array, python, python-2.7
Solution
With this sort of thing, I generally recommend `numpy`:
>>> data = np.array([ [0, 1], [2,3] ])
>>> data[:,0]
array([0, 2])
As far as how python is handling it in your case:
data[:][0]
Makes a copy of the entire list and then takes the first element (which is the first sublist).
data[0][:]
takes the first sublist and then copies it.
Problem
Given `data` as ``` data = [ [0, 1], [2,3] ] ``` I want to index all first elements in the lists inside the list of lists. i.e. I need to index `0` and `2`. I have tried ``` print data[:][0] ``` but it output the complete first list .i.e. ``` [0,1] ``` Even ``` print data[0][:] ``` produces the same result. My question is specifically how to accomplish what I have mentioned. And more generally, how is python handling double/nested lists?