如何将字符串转换为 MongoDB 中的数值？
您需要使用一些代码才能将字符串转换为MongoDB中的数值。
让我们首先创建一个包含文档的集合。使用文档创建集合的查询如下：
> db.convertStringToNumberDemo.insertOne({"EmployeeId":"101","EmployeeName":"Larry"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c7f56528d10a061296a3c31")
}
> db.convertStringToNumberDemo.insertOne({"EmployeeId":"1120","EmployeeName":"Mike"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c7f56648d10a061296a3c32")
}
> db.convertStringToNumberDemo.insertOne({"EmployeeId":"3210","EmployeeName":"Sam"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c7f566e8d10a061296a3c33")
}在find()方法的帮助下显示集合中的所有文档。查询如下-
> db.convertStringToNumberDemo.find().pretty();
以下是输出-
{
"_id" : ObjectId("5c7f56528d10a061296a3c31"),
"EmployeeId" : "101",
"EmployeeName" : "Larry"
}
{
"_id" : ObjectId("5c7f56648d10a061296a3c32"),
"EmployeeId" : "1120",
"EmployeeName" : "Mike"
}
{
"_id" : ObjectId("5c7f566e8d10a061296a3c33"),
"EmployeeId" : "3210",
"EmployeeName" : "Sam"
}这是在MongoDB中将字符串转换为数值的查询。将“EmployeeId”字符串更改为数值。查询如下-
> db.convertStringToNumberDemo.find().forEach(function(x)
... {
... db.convertStringToNumberDemo.update
... (
...
... {
... "_id": x._id,
...
... },
... {
... "$set":
... {
... "EmployeeId": parseInt(x.EmployeeId)
... }
... }
... )
... }
... );现在检查集合中的文档。查询如下-
> db.convertStringToNumberDemo.find().pretty();
以下是显示转换为整数的字符串值(EmployeeId)的输出-
{
"_id" : ObjectId("5c7f56528d10a061296a3c31"),
"EmployeeId" : 101,
"EmployeeName" : "Larry"
}
{
"_id" : ObjectId("5c7f56648d10a061296a3c32"),
"EmployeeId" : 1120,
"EmployeeName" : "Mike"
}
{
"_id" : ObjectId("5c7f566e8d10a061296a3c33"),
"EmployeeId" : 3210,
"EmployeeName" : "Sam"
}