打印 2x2 矩阵

Question

我编写了一个程序来打印一个 2x2 矩阵，其中每个矩阵中表示的数字通过用户输入给出。

例如：

userin = 1 2     #two digit input with a spacing in between
userin2 = 3 4    #userin and userin2 is first matrix
userin3 = 5 6
userin4 = 7 8    #userin3 and userin4 is second matrix
The program would then print out: [[1,2],[3,4]],   #first matrix
                                  [[5,6],[7,8]]    #second matrix

我

让程序按照我想要的方式工作，但我觉得我编写的代码效率很低，以至于我创建了太多的空列表来满足用户的输入。

userin = input("Enter first two digit for first 2x2 matrix: ").split(' ')
userin2 = input("Enter last two digit for first 2x2 matrix: ").split(' ')
userin3 = input("Enter first two digit for second 2x2 matrix: ").split(' ')
userin4 = input("Enter last two digit for second 2x2 matrix: ").split(' ')
lst1 = []
lst2 = []
lst3 = []
lst4 = []
matrix = []
matrix2 = []
for x in userin:
    x = int(x)
    lst1.append(x)
for j in userin2:
    j = int(j)
    lst2.append(j)
for x in userin3:
    x = int(x)
    lst3.append(x)
for j in userin4:
    j = int(j)
    lst4.append(j)
matrix.append(lst1)
matrix.append(lst2)
matrix2.append(lst3)
matrix2.append(lst4)
print(matrix)
print(matrix2)

程序以我想要的格式输出，即 [[1,2]、[3,4]]、[[5,6]、[7,8]]，但我正在寻找一种更有效的方法。

请注意，我不建议使用 numpy 和其他内置库。

感谢您的帮助。

Answer 1

以下是几种替代方法的示例。我不确定第一个例子是你要找的，但我把它扔进去是为了好玩！

>>> userin = '1 2'.split()
... userin2 = '3 4'.split()
... userin3 = '5 6'.split()
... userin4 = '7 8'.split()
>>> print('[[{}, {}], [{}, {}]]'.format(*userin, *userin2))
... print('[[{}, {}], [{}, {}]]'.format(*userin3, *userin4))
[[1, 2], [3, 4]]
[[5, 6], [7, 8]]
>>> print([[int(a) for a in pair] for pair in (userin, userin2)])
... print([[int(a) for a in pair] for pair in (userin3, userin4)])
[[1, 2], [3, 4]]
[[5, 6], [7, 8]]

Answer 2

这就是我会这样做的：

# make a list of lists with the input
userin = [[input("Enter first two digit for first 2x2 matrix: ").strip().split(' '),
                 input("Enter last two digit for first 2x2 matrix: ").strip().split(' ')],
          [input("Enter first two digit for second 2x2 matrix: ").strip().split(' '),
                 input("Enter last two digit for second 2x2 matrix: ").strip().split(' ')]]
for matrix in userin: # loop through inner lists
    for index, row in enumerate(matrix): # loop through each matrix
        matrix[index] = [int(item) for item in row] # convert input to integers
print(",n".join(str(matrix) for matrix in userin)) # print

如果它总是只有这 4 个输入语句，我认为这很好。如果输入是可变的，则创建函数会更有意义。

输出：

Enter first two digit for first 2x2 matrix: 1 2
Enter last two digit for first 2x2 matrix: 3 4
Enter first two digit for second 2x2 matrix: 5 6
Enter last two digit for second 2x2 matrix: 7 8
[[1, 2], [3, 4]],
[[5, 6], [7, 8]]

Answer 3

为什么不放入 while 循环来获取任意数量的矩阵，为什么不一次接收所有 4 个元素？

像这样：

user_in = ['0']
matrices = []
while (user_in[0].lower() != 'q'):
   user_in = input("Input 2x2 matrix(space separated), enter 'q' to quit: ").split(' ')
   if len(user_in) == 4:
      a, b, c, d = user_in
      m2x2 = [[int(a), int(b)], [int(c), int(d)]]
      matrices.append(m2x2)
for matrix in matrices:
    print(matrix)