Question 115175 in Mongodb Question posted in
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Display document value with new format in MongoDB

Companies
[
   { _id: 1, name: "Apple" },
   { _id: 2, name: "Microsoft" },
   { _id: 3, name: "Facebook" },
   { _id: 4, name: "Tesla" }
]

Is there a way to show name filed in query to new format?

Example )

Companies.find({}).newFormat(document => name: document.name[0] + '****')


Expected Result:

[
   { _id: 1, name: "A****" },
   { _id: 2, name: "M****" },
   { _id: 3, name: "F****" },
   { _id: 4, name: "T****" }
]
Tags:

2

Answers


  1. 0

    You can use aggregate like this

    db.Companies.aggregate([
  {
    $addFields: {
      name: {
        $concat: [
          { $substr: ['$name', 0, 1] }, 
          '****'
        ]
      }
    }
  }
])
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  2. 0

    you can do a projection with $concat and $substr with find as well

    db.collection.find({},{
  name: { $concat: [ { $substr: [ "$name", 0, 1 ] }, "****" ]}
})

    playground

    if you want to add a variable number of "*" say based on the length of each name you can use $reduce

    db.collection.aggregate([
  {
    $addFields: {
      name: {
        $reduce: {
          input: { $range: [ 1, { $strLenCP: "$name" }, 1 ] },
          initialValue: { $substr: [ "$name", 0, 1 ] },
          in: { $concat: [ "$$value", "*" ] }
        }
      }
    }
  }
])

    playground

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