def transpose(matrix):
    newmatrix = []
    for i in range(len(matrix)):
        newarrow = []
        for j in range(len(matrix[0])):
            newarrow.append(matrix[j][i])
        newmatrix.append(newarrow)
    matrix = newmatrix
    print(newmatrix)


matrix = [[1, 2], [3, 4]]
transpose(matrix)
print(matrix)