CODEWITHSUNDEEP
mongodbaggregation-frameworkpymongopython-3.7
motipai
motipai

Reputation: 328

select specific field from mongo collection not working

I have a collection called tabelas with datasuch as:

{ "_id" : ObjectId("5cdcd4669dc6d6274f2234dc"), 
  "id" :  "recdj5bcTznLBGtbY", 
  "fields" : { "id_tabela" : "tab0005" }, 
  "createdTime" : "2018-08-13T19:15:26.000Z" }

I am trying to create an array with just the values given by "id_tabela", in this case, my result would be ["tab0005"].

I tried, using pymongo to get first the "fields" values and later to get the id_tabela values. But I am not even getting the fields values.

tabelas = db.get_collection("tabelas")
db.drop_collection("tabelas")
result_tabelas = tabelas.insert_many(lista_tabs)

tabelas = db.get_collection("tabelas") 
tab_array = list(tabelas.find())

vec_fields = tab_array['fields']

The last line results in an error of the kind:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: list indices must be integers or slices, not str

Upvotes: 1

Views: 229

Answers (1)

Ashh
Ashh

Reputation: 46461

You can use aggregation as well

db.collection.aggregate([
  { "$group": {
    "_id": False,
    "array": {
      "$addToSet": "$fields.id_tabela"
    }
  }}
])

Upvotes: 1

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