本文介绍了在二维矩阵(m X n)中找到每一行以及每一列的总和的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
如何在二维矩阵(m X n)中查找每一行以及每一列的总和。
How to find the sum of each row as well as that of each column in 2 dimensional matrix ( m X n).
[
[1, 2, 3],
[3, 2, 1]
]
我知道在一维数组中,我们可以做到:
I know in one dimensional array, we can do:
var sum = [5, 6, 3].reduce(add, 0);
function add(a, b) {
return a + b;
}
console.log(sum);
推荐答案
使用ECMAScript6,您可以执行以下操作:
Using ECMAScript6, you can do:
var matrix = [
[ 1, 2, 3 ],
[ 7, 2, 6 ]
];
// sums of rows
var rowSum = matrix.map(r => r.reduce((a, b) => a + b));
// sums of columns
var colSum = matrix.reduce((a, b) => a.map((x, i) => x + b[i]));
console.log(rowSum);
console.log(colSum);
行的总和很容易说明。让我们考虑一个3x3矩阵,在这里更容易格式化:
The sum of rows is rather easy to illustrate. Let's consider a 3x3 matrix which is easier to format here:
[ 1 2 3 ] -- reduce --> 6 \
[ 7 2 6 ] -- reduce --> 15 } -- map --> [ 6, 15, 7 ]
[ 4 1 2 ] -- reduce --> 7 /
列的总和不那么琐碎。我们通过一次映射两行来减少:
The sum of columns is less trivial. We 'reduce' by 'mapping' 2 rows at a time:
[ 1 2 3 ] [ 8 4 9 ]
+ [ 7 2 6 ] -- reduce --> + [ 4 1 2 ]
--------- ---------
map = [ 8 4 9 ] map = [ 12 5 11 ]
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