在3维数组中查找索引。

huangapple
go评论114阅读模式
英文:

Find the index in the 3 dimensional array

问题

让我们假设我有一个像这样的数组：

  1. const arr = [
  2.   [
  3.     [
  4.       {name: 'Bob'},
  5.       {name: 'John'},
  6.     ],
  7.     [
  8.       {name: 'Maria'},
  9.       {name: 'Marin'},
  10.       {name: 'Marix'},
  11.       {name: 'Alex'}
  12.     ],
  13.   ],
  14.   [
  15.     [
  16.       {name: 'JP'},
  17.       {name: 'Dox'},
  18.       {name: 'Dor'},
  19.       {name: 'Dog'},
  20.     ],
  21.     [
  22.       {name: 'Dol'},
  23.       {name: 'Fol'},
  24.       {name: 'Fol'},
  25.       {name: 'Fol'}
  26.     ],
  27.   ]
  28. ];

我有一个名字，我想在数组中的对象中找到索引。

这是我的解决方案，它有效，但我想找到另一种解决方案，而不使用3个forEach：

  1. const givenName = 'Dox';
  2. let myIndex;
  4. for (let i = 0; i < arr.length; i++) {
  5.   const firstDepth = arr[i];
  6.   for (let j = 0; j < firstDepth.length; j++) {
  7.     const secondDepth = firstDepth[j];
  8.     for (let k = 0; k < secondDepth.length; k++) {
  9.       const lastStep = secondDepth[k];
  10.       if (lastStep && lastStep.name === givenName) {
  11.         myIndex = k;
  12.         break;
  13.       }
  14.     }
  15.     if (myIndex !== undefined) {
  16.       break;
  17.     }
  18.   }
  19.   if (myIndex !== undefined) {
  20.     break;
  21.   }
  22. }

谢谢。

英文:

Let's suppose I have an array like this:

  1. const arr = [
  2.   [
  3.     [
  4.       {name: &#39;Bob&#39;},
  5.       {name: &#39;John&#39;},
  6.     ],
  7.     [
  8.       {name: &#39;Maria&#39;},
  9.       {name: &#39;Marin&#39;},
  10.       {name: &#39;Marix&#39;},
  11.       {name: &#39;Alex&#39;}
  12.     ],
  13.   ],
  14.   [
  15.     [
  16.       {name: &#39;JP&#39;},
  17.       {name: &#39;Dox&#39;},
  18.       {name: &#39;Dor&#39;},
  19.       {name: &#39;Dog&#39;},
  20.     ],
  21.     [
  22.       {name: &#39;Dol&#39;},
  23.       {name: &#39;Fol&#39;},
  24.       {name: &#39;Fol&#39;},
  25.       {name: &#39;Fol&#39;}
  26.     ],
  27.   ]
  28. ];

I have a name and I want to find the index on the object in the array.

There is my solution it works but I want to find another solution without 3 forEach.

  1. const givenName = &#39;Dox&#39;;
  2. let myIndex;
  3. arr.forEach((firstDepth) =&gt; {
  4.   if (firstDepth &amp;&amp; Array.isArray(firstDepth)) {
  5.     firstDepth.forEach((secondDepth, i) =&gt; {
  6.        secondDepth.forEach((lastStep) =&gt; {
  7.         if (lastStep) {
  8.           const { name } = lastStep;
  9.           if (name === givenName) {
  10.              myIndex = i;
  11.           }
  12.         }
  13.       });
  14.     });
  15.   }
  16. });

Thanks.

答案1

得分: 0

You could take a recursive approach and store the indices for each level as return value.

  1. const
  2.     find = (array, name) => {
  3.         var indices ;
  4.         array.some((item, i) => {
  5.             if (Array.isArray(item)) {
  6.                 var temp = find(item, name);
  7.                 if (temp) return indices = [i, ...temp];
  8.                 return false;
  9.             } 
  10.             if (item.name === name) return indices = [i];
  11.         });
  12.         return indices;
  13.     },
  14.     array = [[[{ name: 'Bob' }, { name: 'John' }], [{ name: 'Maria' }, { name: 'Marin' }, { name: 'Marix' }, { name: 'Alex' }]], [[{ name: 'JP' }, { name: 'Dox' }, { name: 'Dor' }, { name: 'Dog' }], [{ name: 'Dol' }, { name: 'Fol' }, { name: 'Fol' }, { name: 'Fol' }]]];
  16. console.log(find(array, 'Dox'));
  17. console.log(find(array, 'foo'));
英文:

You could take a recursive approach and store the indices for each level as return value.

<!-- begin snippet: js hide: false console: true babel: false -->
<!-- language: lang-js -->
const
find = (array, name) => {
var indices ;
array.some((item, i) => {
if (Array.isArray(item)) {
var temp = find(item, name);
if (temp) return indices = [i, ...temp];
return false;
}
if (item.name === name) return indices = [i];
});
return indices;
},
array = [[[{ name: 'Bob' }, { name: 'John' }], [{ name: 'Maria' }, { name: 'Marin' }, { name: 'Marix' }, { name: 'Alex' }]], [[{ name: 'JP' }, { name: 'Dox' }, { name: 'Dor' }, { name: 'Dog' }], [{ name: 'Dol' }, { name: 'Fol' }, { name: 'Fol' }, { name: 'Fol' }]]];

  1. console.log(find(array, &#39;Dox&#39;));
  2. console.log(find(array, &#39;foo&#39;));

<!-- end snippet -->

答案2

得分: 0

感谢您的问题。3维数组很有趣 在3维数组中查找索引。

您可以使用JavaScript方法filter来避免冗余的forEach循环。

以下是我的回答：

  1. const arr = [
  2.   [
  3.     [
  4.       {name: 'Bob'},
  5.       {name: 'John'},
  6.     ],
  7.     [
  8.       {name: 'Maria'},
  9.       {name: 'Marin'},
  10.       {name: 'Marix'},
  11.       {name: 'Alex'}
  12.     ],
  13.   ],
  14.   [
  15.     [
  16.       {name: 'JP'},
  17.       {name: 'Dox'},
  18.       {name: 'Dor'},
  19.       {name: 'Dog'},
  20.     ],
  21.     [
  22.       {name: 'Dol'},
  23.       {name: 'Fol'},
  24.       {name: 'Fol'},
  25.       {name: 'Fol'}
  26.     ],
  27.   ]
  28. ];
  30. const givenName = 'Dox';
  31. let myIndex;
  33. _ = arr.filter(firstDepthArray => {
  34.   firstDepthArray.filter(secondDepthArray => {
  35.     secondDepthArray.filter((thirdDepthObject, i) => {
  36.       let name = thirdDepthObject.name;
  37.       if (name === givenName) {
  38.         myIndex = i;
  39.         console.log("Found Index: " + myIndex + " for Element: " + name);
  40.         return;
  41.       }
  42.     })
  43.   })
  44. });

问候，

AJ

英文:

Thanks for your question. 3-Dimensional Arrays are interesting 在3维数组中查找索引。

You can use the JavaScript Method filter to avoid redundant forEach loops.

Here's my answer:

  1. const arr = [
  2.   [
  3.     [
  4.       {name: &#39;Bob&#39;},
  5.       {name: &#39;John&#39;},
  6.     ],
  7.     [
  8.       {name: &#39;Maria&#39;},
  9.       {name: &#39;Marin&#39;},
  10.       {name: &#39;Marix&#39;},
  11.       {name: &#39;Alex&#39;}
  12.     ],
  13.   ],
  14.   [
  15.     [
  16.       {name: &#39;JP&#39;},
  17.       {name: &#39;Dox&#39;},
  18.       {name: &#39;Dor&#39;},
  19.       {name: &#39;Dog&#39;},
  20.     ],
  21.     [
  22.       {name: &#39;Dol&#39;},
  23.       {name: &#39;Fol&#39;},
  24.       {name: &#39;Fol&#39;},
  25.       {name: &#39;Fol&#39;}
  26.     ],
  27.   ]
  28. ];
  30. const givenName = &#39;Dox&#39;;
  31. let myIndex;
  33. _ = arr.filter(firstDepthArray =&gt; {
  34.   firstDepthArray.filter(secondDepthArray =&gt; {
  35.     secondDepthArray.filter((thirdDepthObject, i) =&gt; {
  36.       let name = thirdDepthObject.name;
  37.       if (name === givenName) {
  38.         myIndex = i;
  39.         console.log(&quot;Found Index: &quot; + myIndex + &quot; for Element: &quot; + name);
  40.         return;
  41.       }
  42.     })
  43.   })
  44. });

Regards,

AJ

答案3

得分: 0

你好，我也尝试使用递归方法。

  1. findItem(array, name) {
  2.     array.forEach((item, index) => {
  3.         if (Array.isArray(item)) {
  4.             this.findItem(item, name);
  5.         } else if (item instanceof Object && item.name === name) {
  6.             console.log(`找到项目 ${item.name} 在索引 ${index}`);
  7.         }
  8.     });
  9. }
  11. this.findItem(arr, 'Alex');
英文:

Hello I also tried with recursive approach.

  1. findItem(array, name) {
  2.     array.forEach((item, index) =&gt; {
  3.       if (Array.isArray(item)) {
  4.         this.findItem(item, name);
  5.       } else if (item instanceof Object &amp;&amp; item.name === name) {
  6.         console.log(`Found item ${item.name} on index ${index}`);
  7.       }
  8.     });
  9. }
  11. this.findItem(arr, &#39;Alex&#39;);

答案4

得分: 0

如果一个名称出现多次怎么办？我认为您想要一个包含该名称的每个“secondDepth”数组的索引列表。

如果您想要缩短您的代码，可以查看JS数组方法。例如，您可以在这里使用map、findIndex()和some()的组合：

  1. const arr = [[[{name: 'Bob'}, {name: 'John'}],[{name: 'Maria'}, {name: 'Marin'}, {name: 'Marix'}, {name: 'Alex'}]], [[{name: 'JP'}, {name: 'Dox'}, {name: 'Dor'}, {name: 'Dog'}], [{name: 'Dol'}, {name: 'Fol'}, {name: 'Fol'}, {name: 'Fol'}]]];
  2. const givenName = 'Dox';
  3. const myIndexes = arr.map(secondDepth => Array.isArray(secondDepth) 
  4.     ? secondDepth.findIndex(thirdDepth => thirdDepth.some(({name}) => name === givenName))
  5.     : false
  6.   )
  7.   .filter(i => i >= 0)
  9. console.log(myIndexes);
英文:

What if one name exists more than once? I think you want a list of indexes for every "secondDepth" -Array that contains the name.

Take a look at JS Array-Methods if u trying to shorten your code. For example you can use a combination of map, findIndex() and some() here:

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

  1. const arr = [[[{name: &#39;Bob&#39;}, {name: &#39;John&#39;}],[{name: &#39;Maria&#39;}, {name: &#39;Marin&#39;}, {name: &#39;Marix&#39;}, {name: &#39;Alex&#39;}]], [[{name: &#39;JP&#39;}, {name: &#39;Dox&#39;}, {name: &#39;Dor&#39;}, {name: &#39;Dog&#39;}], [{name: &#39;Dol&#39;}, {name: &#39;Fol&#39;}, {name: &#39;Fol&#39;}, {name: &#39;Fol&#39;}]]];
  3. const givenName = &#39;Dox&#39;;
  4. const myIndexes = arr.map(secondDepth =&gt; Array.isArray(secondDepth) 
  5.     ? secondDepth.findIndex(thirdDepth =&gt; thirdDepth.some(({name}) =&gt; name === givenName))
  6.     : false
  7.   )
  8.   .filter(i =&gt; i &gt;= 0)
  10. console.log(myIndexes);

<!-- end snippet -->

huangapple
  • 本文由 发表于 2020年1月3日 17:53:22
  • 转载请务必保留本文链接：https://go.coder-hub.com/59576389.html
  • arrays
  • javascript
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