freeCodeCamp/curriculum/challenges/chinese/22-rosetta-code/rosetta-code-challenges/element-wise-operations.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
599c333915e0ea32d04d4bec	元素操作	1	302252	element-wise-operations

--description--

Implement basic element-wise matrix-matrix and scalar-matrix operations.

实现：

• addition
• 减
• 乘
• 除
• 幂

第一个参数将是要执行的操作，例如，“m_add”用于矩阵加法，“s_add”用于标量加法。 第二个和第三个参数将是要在其上执行操作的矩阵。

--hints--

operation 应该是一个函数。

assert(typeof operation === 'function');

operation("m_add",[[1,2],[3,4]],[[1,2],[3,4]]) 应该返回 [[2,4],[6,8]]。

assert.deepEqual(
  operation(
    'm_add',
    [
      [1, 2],
      [3, 4]
    ],
    [
      [1, 2],
      [3, 4]
    ]
  ),
  [
    [2, 4],
    [6, 8]
  ]
);

operation("s_add",[[1,2],[3,4]],2) 应该返回 [[3,4],[5,6]].

assert.deepEqual(
  operation(
    's_add',
    [
      [1, 2],
      [3, 4]
    ],
    2
  ),
  [
    [3, 4],
    [5, 6]
  ]
);

operation("m_sub",[[1,2],[3,4]],[[1,2],[3,4]]) 应该返回 [[0,0],[0,0]]。

assert.deepEqual(
  operation(
    'm_sub',
    [
      [1, 2],
      [3, 4]
    ],
    [
      [1, 2],
      [3, 4]
    ]
  ),
  [
    [0, 0],
    [0, 0]
  ]
);

operation("m_mult",[[1,2],[3,4]],[[1,2],[3,4]]) 应该返回 [[1,4],[9,16]]。

assert.deepEqual(
  operation(
    'm_mult',
    [
      [1, 2],
      [3, 4]
    ],
    [
      [1, 2],
      [3, 4]
    ]
  ),
  [
    [1, 4],
    [9, 16]
  ]
);

operation("m_div",[[1,2],[3,4]],[[1,2],[3,4]]) 应该返回 [[1,1],[1,1]]。

assert.deepEqual(
  operation(
    'm_div',
    [
      [1, 2],
      [3, 4]
    ],
    [
      [1, 2],
      [3, 4]
    ]
  ),
  [
    [1, 1],
    [1, 1]
  ]
);

operation("m_exp",[[1,2],[3,4]],[[1,2],[3,4]]) 应该返回 [[1,4],[27,256]]。

assert.deepEqual(
  operation(
    'm_exp',
    [
      [1, 2],
      [3, 4]
    ],
    [
      [1, 2],
      [3, 4]
    ]
  ),
  [
    [1, 4],
    [27, 256]
  ]
);

operation("m_add",[[1,2,3,4],[5,6,7,8]],[[9,10,11,12],[13,14,15,16]]) 应该返回 [[10,12,14,16],[18,20,22,24]]。

assert.deepEqual(
  operation(
    'm_add',
    [
      [1, 2, 3, 4],
      [5, 6, 7, 8]
    ],
    [
      [9, 10, 11, 12],
      [13, 14, 15, 16]
    ]
  ),
  [
    [10, 12, 14, 16],
    [18, 20, 22, 24]
  ]
);

--seed--

--seed-contents--

function operation(op, arr1, arr2) {

}

--solutions--

function operation(op, arr1, arr2) {
  const ops = {
    add: ((a, b) => a + b),
    sub: ((a, b) => a - b),
    mult: ((a, b) => a * b),
    div: ((a, b) => a / b),
    exp: ((a, b) => Math.pow(a, b))
  };
  const ifm = op.startsWith('m');
  const doOp = ops[op.substring(2)];
  for (let i = 0; i < arr1.length; i++) {
    for (let j = 0; j < arr1[0].length; j++) {
      arr1[i][j] = doOp(arr1[i][j], (ifm) ? (arr2[i][j]) : (arr2));
    }
  }
  return arr1;
}