months = {
    1: "Jan",
    2: "Feb",

}

result = {k: v  for k,v in months.items() if v[0]=='J' }

print (result)

matrix = [[1, 2], [3, 4], [5, 6]]


m = [ [ matrix[][] for j in range(len(matrix)) ]  for i in range(len(matrix))]

