如何在mongodb中删除数组的第n个元素 [英] How to delete n-th element of array in mongodb

问题描述

例如我有这个文件:

db.test.save({
  _id: 1,
  list: [
    { key: "a" },
    { key: "b" },
    { key: "c" },
    { key: "d" },
    { key: "e" }
  ]
})

我需要从列表中删除到第二个元素.

and I need remove to the second element from the list.

现在我分两步完成.我首先取消设置第二个列表元素，但 $unset 运算符不会删除该元素，而是将其修改为 null，然后我从列表中提取任何可为空的值字段:

For now I do that in two steps. I first unset the second list element but the $unset operator doesn't remove the element, it modifies it to null, and after that I pull any nullable value from the list field:

db.test.update({_id: 1}, {$unset: {"list.2": 1}})
db.test.update({_id: 1}, {$pull: {list: null}})

有没有办法在一次操作中做到这一点?

Is there a solution to do that in one operation?

推荐答案

不，不幸的是，您正在做的是目前最好的选择.看看这个问题:在 mongoDb 中，如何通过索引删除数组元素，它链接到 Jira这个问题.

No, unfortunately what you are doing is currently the best option. Have a look at this question: In mongoDb, how do you remove an array element by its index which links to a Jira for this very issue.

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