MongoDB $substrCP Operator
MongoDB $substrCP Operator extracts a substring from the given string expression.
$substrCP Operator in MongoDB
The $substrCP Operator in MongoDB is used in the aggregation pipeline to find substrings from a given string expression.
It uses the Unicode code point index and count to determine the substring. This makes it useful when working with strings that contain non-ASCII characters, as it handles the Unicode code points correctly.
For example: { $substrCP: [ “w3wiki”, 0, 5 ] } will give the output as “Beginner” as 0 is given as starting location, and from there 5 characters need to be taken and hence “Beginner” is the result
Syntax
{ $substrCP: [ <your string expression>, <code point index>, <code point count> ] }
Parameters:
- your string expression: It is a valid string expression with alpha/alphanumeric and also with special characters from which the substring will be extracted.
- code point index: It is a number(non-negative integer) that represents the starting point of the substring
- code point counts: Non-negative integer(number) and it specifies the number of characters that need to be taken from the code point index.
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:
Important Points About MongoDB $substrCP Operator
- The $substrCP operator is used in the aggregation pipeline to extract a substring from a given string expression.
- It uses the Unicode code point index and count to determine the substring.
- The $substrCP operator is useful when working with strings that contain non-ASCII characters, as it handles the Unicode code points correctly.
- The $substrCP operator is designed to work efficiently within the MongoDB aggregation framework, providing a way to manipulate string data based on Unicode code points.
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