如何从mongodb文档中的数组中删除字符串? [英] How do I remove a string from an array in a mongodb document?

问题描述

我一直在解决从mongodb文档中的数组中删除字符串的问题.例如，我想从下面的文档的列表字段中删除条目四".

I've been having trouble with the problem of removing a string from an array in a mongodb document. For example I want to remove the entry "four" from the list field in the document below.

{
  "list" : [ "1", "2", "four", "five", "6"]
}

我知道这似乎很简单，但我无法从文档或先前的问题中找到直接答案.我已经尝试使用db.collection.update结合$ pull和$ mod修饰符对5个左右的命令无效.有帮助吗?

I know it seems very simple but I haven't been able to find a straight answer from the docs or previous questions. I've tried 5 or so commands to no avail using db.collection.update combined with the $pull and $mod modifiers. Any help?

我知道，这是非常基本的问题.

I know, very rudimentary question.

推荐答案

您可以使用 $ Pull 运算符，请尝试以下查询:

You can use $Pull operator, please try the below query :

db.collection.update(
                      { _id : id },
                      { $pull: 
                             { "list":"four" }
                      }
                     );

如果要从arry列表"中删除两个或多个元素，也可以使用$ Pull运算符来完成:

If you want to remove two or more elements from the arry "list", you can do that as well with $Pull operator as well :

db.collection.update( { _id : id },
                      { $pull: 
                              { list : 
                                      { $in : [ "one", "four" ] }
                              }
                       }
                     );

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