从mongo数组中删除null元素

{
        "_id" : 160,
        "info" : [
            {
                'name': 'Serg',
                'proff': 'hacker'
            },
            null,
        ]
    }

As you can see I have null element in my array, I need a general solution that will remove null elements from info array.

正如您所看到的，我的数组中有null元素，我需要一个通用解决方案，它将从info数组中删除null元素。

I tried this:

我试过这个：

for doc in iter:
    people.update({ '_id' : doc['_id']}, { '$pull' : { 'info' : 'null' }})

where iter is a collection of documents. and people is a collection

其中iter是一个文档集合。人是一个集合

I also tried this in the shell:

我也在shell中试过这个：

> db.people.findAndModify({ query: {}, update: {'$pull': {info:null} } } )

But none of the above examples delete this null from my documents!! ))

但上述示例都没有从我的文档中删除此null！））

1 个解决方案

#1

This should work out for you. In python null is called None.

这应该适合你。在python中，null称为None。

    for doc in iter:
        people.update({'_id':doc[id]},{'$pull':{'info':None}})

null object in Python?

Python中的null对象？

Also in mongo shell, this should work out:

同样在mongo shell中，这应该是有效的：

    db.people.update({_id:160},{$pull:{info:null}})

If you want the update operator, to update more that one document at a time, that is to pull out null values from multiple documents, then you have to supply the multi:true option. Because by default, if the query arguemnt is left blank i.e. {} and mulit:true is not provided, update operator works on the first document that it finds

如果您想要更新运算符，要一次更新多个文档，即从多个文档中提取空值，则必须提供multi：true选项。因为默认情况下，如果查询arguemnt保留为空，即{}并且未提供mulit：true，则update运算符将对其找到的第一个文档进行处理

    db.people.update({},{$pull:{info:null}},{multi:true})

#1