declare an empty 2d list in python code example

Example 1: python initialize a 2d array

x = [[foo for i in range(10)] for j in range(10)]
# x is now a 10x10 array of 'foo' (which can depend on i and j if you want)

Example 2: how to create 2d list in python

o=[]
for i in range(0,rows):
    x=[]
    for j in range(0,cols):
        x.append(0)
    o.append(x)
#if you use [[0]*cols]*rows all rows will become the same list
#so editing in one row will edit all rows