Using a regex with text search in MongoDB - node.js

I have created a text index on the num field in the collection. Now while passing the string to search from the text index, I need to use a regex which has to be passed as a string to the $search variable.
My current query works fine but it doesn't work when I add a regex to it.
Current Query:
db.collection.find({$text:{$search:"1234 6789"}},{'id':1})
I need to add a regex/like query to the $search to make it something like
db.collection.find({$text:{$search:"/1234/ /6789/"}},{'id':1})
where I get all the values from the database that contain a pattern like "1234" OR "6789".
I did try the query but it gives me a $search needs a String error:
db.collection.find({$text:{$search:/1234/}},{'id':1})

To achieve this you should use the $regex MongoDB operator:
// Without options
db.collection.find({num: /1234|5678/i});
// Separate options property
db.collection.find({num: {$regex: /1234|5678/, $options: 'i'}});
To add multiple terms in the regex, use the | operator
$regex docs and examples
Edit:
For querying records using an array of values the $in operator can be used:
$in docs and examples

Related

how to find a string in another one without using find() method in python

I have the following code:
def light():
result = collection1.find({"deviceName": })
lights_id = []
for x in result:
lights_id.append(x["_id"])
return lights_id
I need to fetch in a database for a device name containing the string light, and I need to fill it in the blank but I don't know how to do it in this case.
Assuming your collecyion1 is a mongodb collection, i think this should work
collection1.find({'deviceName': {'$regex': ".*light.*", '$options': 'i'}})
as mongodb supports regex, we are searching a text using regex in this case
./*light.* and passing option i so that the match is case insensetive.

get list of collections having all words exists in field which added in given string in mongoDB

I want to search list of collections from mongoDB have all the keywords of given string.
For e.g.
I have a collection
{
"id":1
"text":"go for shopping",
"description":"you can visit this branch as well"
}
{
"id":2
"text":"check exiting discount",
"description":"We have various discount options"
}
Now, If I will pass string like "I want to go for shopping" w.r.t. text field in find query of mongoDB. Then I should get first collection as output because text field value "go for shopping" exists in the input string passed in find query.
This can be achieved through $text operator in MongoDB. But you have to createIndex on the "text" field in your database.(or whichever filed you want to be matched, I would suggest you rename it in your db to avoid confusion)
db.yourCollectionName.createIndex({"text":"text"})
The first field here is the "text" field in your database, and the second one is the mongo operator.
Then you can pass any query like,
db.yourCollectionName.find({$text: {$search: "I want to go for shopping"}})
The "$text" here is the mongo operator.
This would return all documents which have any of the keywords above.
Maybe you can read more around this and improvise and modify.
Ref: MongoDb $text
You can do so through regular expression. MongoDb provides the provision of matching strings through regex patterns.
In your case you could do something like:
db.yourCollectionName.find({text:{$regex:"go for shopping" }})
This will return you all the documents having the phrase "go for shopping" in the text field.
Ref: MongoDb Regex

How to search full or partial match with first name and last name in mongodb

How to search full or partial match with first name and last name in mongodb?
I tried using this,
{"name":{ $regex: str, $options: 'i'}}
But it is only for full match of the string.
Can I use regex for partial match?
For this type of search better to create text index. mongo shell command to create text index for name field.
db.colectionName.createIndex( { name: "text" } );
then you can search using $text and $search
var text = 'John Test''
db.collectionName.find({ $text: { $search: text } });
for this query you will get if name contain john or test and this is case insensitive
I have to do this for my project, how does this work for you? {"name":new RegExp('^'+name, 'i')} you may need to encode the string first str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
Try this
{'name': {'$regex': '.*str.*', $options: 'i'}}
I have responded to similar question here, combining text index and regex pattern makes it work nicely. Note, text index is searching by terms so if you try to search for padavan by supplying pad you won't get what you are expecting having only text index in place.

How to get all matches with MongoDB $elemMatch?

I have two objects:
{
genre: ['music', 'movie']
}
and
{
genre: ['movie', 'music']
}
and my query is:
db.test.find({genre :{ $elemMatch:{ $in : ['movie']}}})
and it only gives me the second object. Why? I want to get all the docs that contain a specific genre in their arrays no matter where in the array. How can I do this?
You need neither $elemMatch nor $in in this case. A simple field:value will match documents where field is an array and any one of the values in that array is value. That means
db.test.find({genre :'movie'});
will suffice.
The array query operators are required in more complex situations.
$in is needed when you have a list of possible values and want documents where any of them is found (so db.test.find({genre : { $in:['movie']} }); would work, but would be needlessly convoluted)
$all works like $in but requires that all provided elements are in the array
$elemMatch is a bit more complex. It is required when you want to use multiple operator-conditions (like $gt or $lt) but want only those documents where one array entry matches all the conditions. Without the $elemMatch operator, you get results where each condition is met by at least one array entry, but not necessarily all by the same entry.
Remember db.test.find() in general returns you cursor object. You can access all doc as follows:
entry = db.test.find({genre :{ $elemMatch:{ $in : ['movie']}}})
for doc in entry:
print(doc)

How do you do a contains query using the MongoDB node.js driver?

I'm trying to do a search on items that contain a certain substring, but I'm getting no results back (even though I know the data is right for the query, including case):
collection.find({name: "/.*" + keyword + ".*/"}).toArray(function(err, items)
Should that not match everything that contains the keyword? It just returns an empty object.
I'm just using the regular MongoDB driver in an ExpressJS app.
You need to build a regular expression first should try something like this:
var regex = RegExp("/.*" + keyword + ".*/")
Then pass in the variable to the query. I generally find it easier to do the query as a variable and pass that in:
var query = { FieldToSearch: new RegExp('^' + keyword) };
collection.find(query).toArray(...)
I've included the regex as a left rooted regex to take advantage of indexes (always recommended if possible for performance). For more take a look here:
http://www.mongodb.org/display/DOCS/Advanced+Queries#AdvancedQueries-RegularExpressions
I did it like this
keyword = "text_to_search";
collection.find({name: {$Regex: keyword, $options:$i }})
I used i $i make the query case insensitive but u can use other options too
try this:
var keyword = req.params.keywords;
var regex = RegExp(".*" + keyword + ".*");
Note.find({noteBody: regex, userID: userID})
I got the keywords from the request parameters and I want to search from the noteBody with these keywords, now the keywords is a variable. If you want to put a variable in the database find, the format must be var regex = RegExp("." + keyword + "."). Hope this helps. Thanks

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