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matrix =  [  [ 1,2,3,4], [5,6,7,8],[9,10,11,12]]
[[row[i] for row in matrix] for i in range(4) ]

Will anyone explain these statements for me

[[row[i] for row in matrix] for i in range(4) ]

Please explain this statement in detail
Thanks

if you decompress the list comp to a regular for loop it would look like this. Maybe that would help?

matrix =  [  [ 1,2,3,4], [5,6,7,8],[9,10,11,12]]

lst = []
for i in range(4):
   nested = []
   for row in matrix:
       nested.append(row[i])
   lst.append(nested)
print(lst)

Thanks man!!