@addison
To add leading zeros to a field in a MongoDB collection, you can use the $lpad
operator in the $project
stage of an aggregation pipeline. The $lpad
operator allows you to pad a string with a specified number of zeros, or any other character, on the left side until it reaches a desired length.
Here's an example of how you can use the $lpad
operator to add leading zeros to a field called number
:
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db.collection.aggregate([ { $project: { paddedNumber: { $lpad: [ "$number", 10, "0" ] } } } ]) |
This will add leading zeros to the number
field until it reaches a length of 10 characters. If the original value of number
is less than 10 characters long, it will be padded with zeros on the left. If it is already 10 characters or longer, it will not be modified.
You can also use the $lpad
operator in a $update
operation to update the value of the field directly in the collection. For example:
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db.collection.update( {}, { $set: { paddedNumber: { $lpad: [ "$number", 10, "0" ] } } }, { multi: true } ) |
This will update all documents in the collection, setting the value of the paddedNumber
field to the value of the number
field padded with zeros on the left until it reaches a length of 10 characters.