Answers for "2d array creation in python"

2d array python initialize

>>> b = [['a']*3]*3
>>> b
[['a', 'a', 'a'], ['a', 'a', 'a'], ['a', 'a', 'a']]
>>> b[1][1]
'a'
>>> b[1][1] = 'b'
>>> b
[['a', 'b', 'a'], ['a', 'b', 'a'], ['a', 'b', 'a']]

python 2d matrix declare

length, breadth = x, y
matrix = [[-1 for j in range(breadth)] for i in range(length)]
# every element is -1