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，我有此文档:

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第二个元素.

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

目前，我分两个步骤进行操作.我首先取消设置第二个列表元素，但是$unset运算符不会删除该元素，而是将其修改为null，然后我从列表字段中拉出任何可为空的值:

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}})

有一种解决方案可以一次完成吗?

Is there a solution to do that in one operation?

推荐答案

否，不幸的是，您目前正在做的是最好的选择.看一下这个问题:在mongoDb中，如何通过其索引删除数组元素，该元素链接到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.

这篇关于如何在MongoDB中删除数组的第n个元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！