MongoDB $substrCP Operator Examples

To understand it better, let’s look at some examples of the MongoDB $substrCP operator.

In the following examples, we are working with:

Database: w3wiki
Collection: articles
Documents: three documents that contain the details of the articles in the form of field-value pairs.

Using $substrCP operator Example

Now, displaying the above article’s output by splitting the “publishedon” column details as “publicationmonth” and “publicationyear” by using the below query:

db.articles.aggregate(

 [

   {

     $project: {

       articlename: 1,

       publicationmonth: { $substrCP: [ "$publishedon", 0, 4 ] },

       publicationyear: {

         $substrCP: [

           "$publishedon", 4, { $subtract: [ { $strLenCP: "$publishedon" }, 4 ] }

         ]

       }

     }

   }

 ]

)

Here, “publicationmonth” is following straight syntax and it picks the first 4 characters of “publishedon” column. In “publicationyear”, rest of the characters of “publishedon” are taken. It uses “$subtract” which is used for subtracting the byte index from the length of the string by using $strLenCP.

Output:

MongoDB $substrCP Operator extracts a substring from the given string expression.