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how to sum arrays of array?

问题描述


英文原文

I know we can sum the array elements using reduce() but what if we have an array of arrays. For eg:

var result=[10,20,30];
result.reduce((a, b) => a + b)

it will return 60

but if we have

result=[
  [10,20,30],
  [20,30,40],
  [60,70,80]
]
console.log(result);

how can we get the final result as result=[60,90,210] using reduce?


中文翻译

I know we can sum the array elements using reduce() but what if we have an array of arrays. For eg:

var result=[10,20,30];
result.reduce((a, b) => a + b)

it will return 60

but if we have

result=[
  [10,20,30],
  [20,30,40],
  [60,70,80]
]
console.log(result);

how can we get the final result as result=[60,90,210] using reduce?

I know we can sum the array elements using reduce() but what if we have an array of arrays. For eg:

var result=[10,20,30];
result.reduce((a, b) => a + b)

it will return 60

but if we have

result=[
  [10,20,30],
  [20,30,40],
  [60,70,80]
]
console.log(result);

how can we get the final result as result=[60,90,210] using reduce?

I know we can sum the array elements using reduce() but what if we have an array of arrays. For eg:

var result=[10,20,30];
result.reduce((a, b) => a + b)

it will return 60

but if we have

result=[
  [10,20,30],
  [20,30,40],
  [60,70,80]
]
console.log(result);

how can we get the final result as result=[60,90,210] using reduce?

2个回答

    最佳答案

  1. 英文原文

    fisrt you can map and inside map use reduce

    result=[
      [10,20,30],
      [20,30,40],
      [60,70,80]
      ]
    const final = result.map(item => item.reduce((a, b)=> a + b, 0))
    
    console.log(final)


    中文翻译

    fisrt you can map and inside map use reduce

    result=[
      [10,20,30],
      [20,30,40],
      [60,70,80]
      ]
    const final = result.map(item => item.reduce((a, b)=> a + b, 0))
    
    console.log(final)

  2. 参考答案2

  3. 英文原文

    result = result.map(subArray => subArray.reduce((a, b) => a + b))
    

    中文翻译

    result = result.map(subArray => subArray.reduce((a, b) => a + b))