Question

I have a data:

{'_id': 0, 'values': [{'value': 1, 'value_type': 'type1'}, {'value': 2, 'value_type': 'type2'}, {'value': 134, 'value_type' : 'type1'}, {'value': 2564, 'value_type': 'type212'}]} 
{'_id': 1, 'values': [{'value': 136, 'value_type': 'type1'}, {'value': 465652, 'value_type': 'type1'}, {'value': 4, 'value_type' : 'type299'}, {'value': 112564, 'value_type': 'type2456'}]}

I’m working with pymongo 2.2 and Python 3.2.

The goal is to find the dictionary (value and value_type) which has value_type is equal to type1 and minimal value of value to remove them. In my case, that’s {'value': 1, 'value_type': 'type1'} and {'value': 136, 'value_type': 'type1'} and I want to remove them.

How do I to achieve that?

–Edit–

I’m aware how to update (delete in my case), I’ll be using $unset operator. What I’m unaware is how to find the values I need to remove.

Answer 1

Use the $pull operator like this:

value = 150
coll.update({}, 
    {'$pull': {'values': {'value_type': 'type1', 'value': {'$lt': value}}}},
    multi=True)

Setting the multi parameter to True tells the update to update all documents, not just the first one.