update an array element in mongodb

Question

I am trying to update an array element inside a document without changing whole array.

Array elements look like this

Suppose i have to only update index 1 element's value. For that i have:

1. _id of the document

2. index 1's value ("optionalImages-624476a7bd4d2bfe6bf86e9a-1-1650025533684.jpeg")

3. to be updated value ("optionalImages-624476a7bd4d2bfe6bf86e9a-1-1650025534589.jpeg").

I think it can be updated by mongodb's arrayfilters but i don't get the documentation correctly. Your help will be highly appreciated.

Answer 1

Query1

• arrayFilters using $[m] inside the path to specify the member value that we want to change
• m is the member with value 20, and we set it to 100
  (instead of 20 and 100, put your "....jpg" strings)

Playmongo

update(
{"_id": {"$eq": 1}},
{"$set": {"ar.$[m]": 100}},
{"arrayFilters": [{"m": {"$eq": 20}}])

Query2

• pipeline update >= MongoDB 4.2
• uses map on the array to
• find the member with value 20, and replaces it with 100

Playmongo

update(
{"_id": {"$eq": 1}},
[{"$set": 
   {"ar": 
     {"$map": 
       {"input": "$ar",
        "in": {"$cond": [{"$eq": ["$$this", 20]}, 100, "$$this"]}}}}}])