Develop Reference

Pandas store column value queried by index as a list

Hi I am trying to store the value I printed by queried the data frame using index, I tried use .tolist and list but I cannot store them. If there any way I can store these values and make the two query results together in one data frame?
Thank you in advance!
I tried use .tolist and list but I cannot store them.

Mongodb get new values from collection without timestamp

I want to fetch added new values from mongodb collections without timestamp value. I guess only choice using objectid field. I using test dataset on github. "https://raw.githubusercontent.com/mongodb/docs-assets/primer-dataset/primer-dataset.json"
For example if I add new data to this collection, how ı fetch or how ı find these new values.
Some mongodb collections using timestamp value, and I use this timestamp value for get new values. But ı do not know, how ı find without timestamp.
Example dataset ;
enter image description here
I want like this filter. but it doesn't work
{_id: {$gt: '622e04d69edb39455e06d4af'}}

If you don't want to create a new field in the document.
SomeGlobalObj = ObjectId[] // length limit is 10
// you will need Redis or other outside storage if you have multi server
SomeGlobalObj.shift(newDocumentId)
SomeGlobalObj = SomeGlobalObj.slice(0,10)
//Make sure to keep the latest 10 IDs.
Now, if you want to retrieve the latest document, you can use this array.
If the up-to-date thing you're talking about is, disappears after checking, you can remove it from this array after query.

In the comments you mentioned that you want to do this using Python, so I shall answer from that perspective.
In Mongo, an ObjectId is composed of 3 sections:
a 4-byte timestamp value, representing the ObjectId's creation, measured in seconds since the Unix epoch
a 5-byte random value generated once per process. This random value is unique to the machine and process.
a 3-byte incrementing counter, initialized to a random value
Because of this, we can use the ObjectId to sort or filter by created timestamp. To construct an ObjectId for a specific date, we can use the following code:
gen_time = datetime.datetime(2010, 1, 1)
dummy_id = ObjectId.from_datetime(gen_time)
result = collection.find({"_id": {"$lt": dummy_id}})
Source: objectid - Tools for working with MongoDB ObjectIds
This example will find all documents created before 2010/01/01. Substituting $gt would allow this query to function as you desire.
If you need to get the timetamp from an ObjectId, you can use the following code:
id = myObjectId.generation_time

django-tables2 doesn't sort columns properly

In the project, I have used RequestConfig(request).configure(table) to apply sorting across the columns. All of them are defined as ArrayField(models.CharField(max_length=50), null= True) . The problem is that the title and year can be sorted, but the other three cannot be sorted properly. I get larger values among the smaller ones. I suppose the Title and Year are strings, but the others are lists containing integers. Can some one have a lead on how to properly sort the three columns in the middle ?Table Headers
Second column not sorted properly

This appears to be the result of sorting integers that are stored as strings. You have pointed out that the columns of your table are defined using a CharField model, which according to the Django docs, is for storing strings.
You should probably define each of the CoAuthors, Citations, and Ncitations columns using IntegerField.

ibm_db.execute- how to get the result set

Newbie working with db2. Developing a python script using ibm_db package. I have a select query where i am binding params using ibm_db.bind_param(stmt, 1,param1). and then doing a result = ibm_db.execute(stmt). How can I get the results from the query. the documentation is scarce on this topic. Would appreciate any example code.

After ibm_db.execute(stmt) you need to fetch data from a result
try this:
data = ibm_db.fetch_assoc(stmt)
Fetch data from a result set by calling one of the fetch functions.
ibm_db.fetch_tuple: Returns a tuple, which is indexed by column position, representing a row in a result set. The columns are 0-indexed.
ibm_db.fetch_assoc: Returns a dictionary, which is indexed by column name, representing a row in a result set.
ibm_db.fetch_both: Returns a dictionary, which is indexed by both column name and position, representing a row in a result set.
ibm_db.fetch_row: Sets the result set pointer to the next row or requested row. Use this function to iterate through a result set.

Study the examples for fetching result-sets in Python with ibm_db, that are in the Db2 knowledge center online at this link

group by in django

How can i create simple group by query in trunk version of django?
I need something like
SELECT name
FROM mytable
GROUP BY name
actually what i want to do is simply get all entries with distinct names.

If you need all the distinct names, just do this:
Foo.objects.values('name').distinct()
And you'll get a list of dictionaries, each one with a name key. If you need other data, just add more attribute names as parameters to the .values() call. Of course, if you add in attributes that may vary between rows with the same name, you'll break the .distinct().
This won't help if you want to get complete model objects back. But getting distinct names and getting full data are inherently incompatible goals anyway; how do you know which row with a given name you want returned in its entirety? If you want to calculate some sort of aggregate data for all the rows with a given name, aggregation support was recently added to Django trunk and can take care of that for you.

Add .distinct to your queryset:
Entries.objects.filter(something='xxx').distinct()

this will not work because every row have unique id. So every record is distinct..
To solve my problem i used
foo = Foo.objects.all()
foo.query.group_by = ['name']
but this is not official API.