Develop Reference

Django: how to use a variable key filter with __range

date_one = form.cleaned_data.get('date_one')
date_two = form.cleaned_data.get('date_two')
date_type = form.cleaned_data.get('date_type')
search = MyClass.objects.filter(date_type__range(date_one, date_two))
My model has two different date columns. (created and expires). The user can make a query filtering between two dates, but he can choose if he wants to filter by creation or expiration.
I could make two query lines using if, but I really want to know how to do it in the way I'm asking.
How can I do this? Since the key before __range is a variable. I tried with (**{ filter: search_string }) but it seems not to be compatible with __range.

try this
filter_dict = {"{}__range".format(date_type): [date_one, date_two]}
search = MyClass.objects.filter(**filter_dict)

The thing you attempted is almost correct!
Lookups are not functions (so it's not foo__range(start, end)), but they are keyword arguments: foo__range=(start, end)
So you would have:
date_one = form.cleaned_data.get('date_one')
date_two = form.cleaned_data.get('date_two')
date_type = form.cleaned_data.get('date_type')
query_kwargs = {
"{}__range".format(date_type): (date_one, date_two)
}
search = MyClass.objects.filter(**query_kwargs)

Get last row of View by couchbase query

i have a query which returns me a Viewobject with all the entries i want to process. I know i can iterate over this view Object so that i can use the single entries for my purposes.
Now i want to extract only the first and the last row. The first row is no problem because i can just iterate and break the loop after the first item.
Now my question is, how to get the last element from the View.
I tried by:
for row in result_rows:
rowvalue = row[3].value
diagdata = rowvalue[models.DIAGDATA]
if models.ODOMETER in diagdata:
start_mileage = diagdata[models.ODOMETER]
start_mileage_found = True
break
row = result_rows[len(result_rows)]
rowvalue = row[3].value
diagdata = rowvalue[models.DIAGDATA]
if models.ODOMETER in diagdata:
end_mileage = diagdata[models.ODOMETER]
end_mileage_found = True
The second value i obviously wont get, because view has neither a length nor can i access the rows by a index. Has anyone an idea how to get the last element?

You might run another request but with descending=True option, so that the server will stream results in reverse order.
Or you can convert iterator to array which basically the same a iterate through all values. I'm not a python expert, but it seems like list(result_rows) will do it for you. And when you are doing len(...) it probably doing it for you implicitly. There is rows_returned method to get the number of rows without turning it to list.

Django querying using array for column value

I'm making a search function for my website that breaks the entered text by spaces and then checks each work with __contains. I want to expand this so that I can pass through what columns I want it to check __contains with such as "First name", "Last Name"... ect.
What I have now:
def getSearchQuery(search,list,columns=None):
"""
Breaks up the search string and makes a query list
Filters the given list based on the query list
"""
if not columns:
columns = { name }
search = search.strip('\'"').split(" ")
for col in columns:
queries = [Q(col__contains=value) for value in search]
query = queries.pop()
for item in queries:
query |= item
return list.filter(query)
Issue is Q(col__contains=value) doesnt work as "col" is not a column. Is there some way to tell django that that is a variable and not the actual column? I have tried googling this but honestly dont know how to phrase it without putting all my code.

Do it this way:
import operator
from functools import reduce
def getSearchQuery(search, list, columns=None):
"""
Breaks up the search string and makes a query list
Filters the given list based on the query list
"""
if not columns:
return list
search = search.strip('\'"').split(" ")
queries = []
for col in columns:
queries.extend([Q((col+'__icontains', value)) for value in search])
return list.filter(reduce(operator.or_, queries))

Python Query Result in QTreeWidget

I am working on python plugins.I used PyQt4 Designer.
I want to list query result into QTreeWidget.
My code is as follows:
c = self.db.con.cursor()
self.db._exec_sql(c, "select est from bio")
for row in c.fetchall():
item_value=unicode(row[0])
top_node1 = QTreeWidgetItem(item_value)
self.treeWidget.insertTopLevelItem(0, top_node1)
The query returns the values as:
But when i list these values into QTreeWidget using above code,it is shown as below :
Only first character is shown.If i change '0' to some other number in self.treeWidget.insertTopLevelItem(0, top_node1) ,nothing appears in QTreeWidget.
How do i do it????
thanx.

If you take a look at the documentation for a QTreeWidgetItem, you will see there are a number of possible constructors for creating an instance. Though none of which it seems you are using in a way that is going to give you desirable results. The closest match to the signature you are providing is:
QTreeWidgetItem ( const QStringList & strings, int type = Type )
What this is probably doing is taking your string (I am assuming row[0] is a string because I don't know which drivers you are using) and applying it as a sequence, which would fullfill the requiremets of QStringList. Thus what you are getting is populating multiple columns of your item with each letter of your string value. If this is what you wanted, then you would n eed to tell your widget to show more columns: self.treeWidget.setColumnCount(10). But this isn't what you are looking for I am sure.
More likely what you should be trying is to create a new item, then add the value to the desired column:
item = QTreeWidgetItem()
item.setText(0, unicode(row[0]))
self.treeWidget.insertTopLevelItem(0, item)
You can use the default constructor with no arguments, set the text value of the first column to your database record field value, and then add that item to the tree. You could also build up a list of the items and add them at once:
items = []
for row in c.fetchall():
item = QTreeWidgetItem()
item.setText(0, unicode(row[0]))
items.append(item)
self.treeWidget.insertTopLevelItems(0, items)

Your first aproach could be corrected just add a list to the widgetitem not a string like this:
top_node1 = QTreeWidgetItem([item_value])

use slice in for loop to build a list

I would like to build up a list using a for loop and am trying to use a slice notation. My desired output would be a list with the structure:
known_result[i] = (record.query_id, (align.title, align.title,align.title....))
However I am having trouble getting the slice operator to work:
knowns = "output.xml"
i=0
for record in NCBIXML.parse(open(knowns)):
known_results[i] = record.query_id
known_results[i][1] = (align.title for align in record.alignment)
i+=1
which results in:
list assignment index out of range.
I am iterating through a series of sequences using BioPython's NCBIXML module but the problem is adding to the list. Does anyone have an idea on how to build up the desired list either by changing the use of the slice or through another method?
thanks zach cp
(crossposted at [Biostar])1

You cannot assign a value to a list at an index that doesn't exist. The way to add an element (at the end of the list, which is the common use case) is to use the .append method of the list.
In your case, the lines
known_results[i] = record.query_id
known_results[i][1] = (align.title for align in record.alignment)
Should probably be changed to
element=(record.query_id, tuple(align.title for align in record.alignment))
known_results.append(element)
Warning: The code above is untested, so might contain bugs. But the idea behind it should work.

Use:
for record in NCBIXML.parse(open(knowns)):
known_results[i] = (record.query_id, None)
known_results[i][1] = (align.title for align in record.alignment)
i+=1

If i get you right you want to assign every record.query_id one or more matching align.title. So i guess your query_ids are unique and those unique ids are related to some titles. If so, i would suggest a dictionary instead of a list.
A dictionary consists of a key (e.g. record.quer_id) and value(s) (e.g. a list of align.title)
catalog = {}
for record in NCBIXML.parse(open(knowns)):
catalog[record.query_id] = [align.title for align in record.alignment]
To access this catalog you could either iterate through:
for query_id in catalog:
print catalog[query_id] # returns the title-list for the actual key
or you could access them directly if you know what your looking for.
query_id = XYZ_Whatever
print catalog[query_id]