$或mongodb 3.4中的合计

Question

I am trying hard to familiarize my self with pymongo and mongodb This query is very basic and very easy, but I am struggling to make it works

match = { "$match": {"$or" : [{"book.author" : ".*"+name+".*"},
                      {"book.editor" : ".*"+name+".*"},
                     {"book.illustrator" : ".*"+name+".*"}]}}
count = {"$count": "tot"}
cur = db.collection.aggregate([match, count])

I am using mongodb 3.4 which provides all of that pipeline stages. I don't know why it return null while the data is exists.

Answer 1

Your regular expression syntax is wrong. If you want to do a wildcard search you will need to use a regular expression operator $regex like so (the $options: 'i' part is to make the search case-insensitive):

match = { "$match": {"$or" : [{"book.author" : {"$regex": name, "$options": "i"}},
                      {"book.editor" : {"$regex": name, "$options": "i"}},
                     {"book.illustrator" : {"$regex": name, "$options": "i"}}]}}
count = {"$count": "tot"}
cur = db.collection.aggregate([match, count])