This is a nested list:
matrix = [['0', '0', '0', '0', '0', '1', '1', '0', '0', '0'],
['0', '1', '1', '1', '1', '1', '0', '0', '0', '0'],
['0', '0', '1', '1', '0', '1', '0', '1', '1', '0'],
['0', '1', '0', '0', '0', '0', '1', '0', '0', '1'],
['0', '0', '0', '1', '0', '0', '1', '0', '1', '0'],
['0', '0', '0', '0', '1', '0', '1', '1', '1', '0'],
['0', '1', '1', '1', '1', '0', '1', '1', '1', '1'],
['1', '1', '1', '1', '1', '1', '1', '1', '1', '1']]
#output should be [1,2,2,2,3,1,5,3,4,2]
Height = 8
Width = 10
I want to know how I can get the height of each collumn. And then each height, I want to put it in a list.
We counting 1's and they only count for the height if they are adjoint 1's.
We start with counting below and then go up.
#output should be [1,2,2,2,3,1,5,3,4,1]
I only want to use build in Python functions.
I tried with a for loop and if, else statements.
For loop iterate through the list.
like if i == '1' add 1 to counter.
if i == '0' reset counter and add the last value from counter to counter1, but only if counter is greater then counter1.
CodePudding user response:
You can use itertools.takewhile
on the reversed, zipped matrix:
from itertools import takewhile
out = [len(list(takewhile(lambda x: x=='1', reversed(l)))) for l in zip(*matrix)]
output:
[1, 2, 2, 2, 3, 1, 5, 3, 4, 2]
If you don't want to import takewhile
, use the recipe:
def takewhile(predicate, iterable):
# takewhile(lambda x: x<5, [1,4,6,4,1]) --> 1 4
for x in iterable:
if predicate(x):
yield x
else:
break
How it works:
zip
rotates the matrix:
>>> list(zip(*matrix))
[('0', '0', '0', '0', '0', '0', '0', '1'),
('0', '1', '0', '1', '0', '0', '1', '1'),
('0', '1', '1', '0', '0', '0', '1', '1'),
('0', '1', '1', '0', '1', '0', '1', '1'),
('0', '1', '0', '0', '0', '1', '1', '1'),
('1', '1', '1', '0', '0', '0', '0', '1'),
('1', '0', '0', '1', '1', '1', '1', '1'),
('0', '0', '1', '0', '0', '1', '1', '1'),
('0', '0', '1', '0', '1', '1', '1', '1'),
('0', '0', '0', '1', '0', '0', '1', '1')]
The list comprehension with reversed
rotates the other way around (actually inverses each row):
>>> [list(reversed(l)) for l in zip(*matrix)]
[['1', '0', '0', '0', '0', '0', '0', '0'],
['1', '1', '0', '0', '1', '0', '1', '0'],
['1', '1', '0', '0', '0', '1', '1', '0'],
['1', '1', '0', '1', '0', '1', '1', '0'],
['1', '1', '1', '0', '0', '0', '1', '0'],
['1', '0', '0', '0', '0', '1', '1', '1'],
['1', '1', '1', '1', '1', '0', '0', '1'],
['1', '1', '1', '0', '0', '1', '0', '0'],
['1', '1', '1', '1', '0', '1', '0', '0'],
['1', '1', '0', '0', '1', '0', '0', '0']]
takewhile
keepd the elements while the condition is True, here while the items are '1'
(lambda x: x=='1'
), and len
gets the length of the output:
>>> l = ['1', '1', '1', '0', '0', '0', '1', '0']
>>> list(takewhile(lambda x: x=='1', l))
['1', '1', '1']
>>> len(list(takewhile(lambda x: x=='1', l)))
3
NB. functions like zip
, reversed
, takewhile
are generators, they don't produce output unless something consumes it, that's why I used list(generator(…))
in the exammples
solution with classical python loops:
out = []
for l in zip(*matrix):
counter = 0
for elem in reversed(l):
if elem == '1':
counter =1
else:
break
out.append(counter)