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Does SQLAlchemy have an equivalent of Django's get_or_create?
... the session had previously queried the model in the same transaction. The best solution I could come up with is to call session.commit() before this query, which is also not ideal since the user may not expect it. The referenced answer does not have this problem since the session.rollback() has the...
Python dict how to create key or append an element to key?
...ections.defaultdict(list)
...
dict_x[key].append(value)
Pros: Probably best performance. Cons: Not available in Python 2.4.x.
Using dict().setdefault():
dict_x = {}
...
dict_x.setdefault(key, []).append(value)
Cons: Inefficient creation of unused list()s.
Using try ... except:
dict_x = ...
Determine version of Entity Framework I am using?
...If you open the references folder and locate system.data.entity, click the item, then check the runtime version number in the Properties explorer, you will see the sub version as well. Mine for instance shows runtime version v4.0.30319 with the Version property showing 4.0.0.0. The EntityFramework.d...
Finding a substring within a list in Python [duplicate]
...56', 'ghi789']
new_list = [x for x in old_list if re.search('abc', x)]
for item in new_list:
print item
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How to store arrays in MySQL?
...es (SQL is exactly that) work using relations, and most of the time, it is best if you assign one row of a table to each "bit of information". For example, where you may think "I'd like a list of stuff here", instead make a new table, linking the row in one table with the row in another table.[1] Th...
ElasticSearch - Return Unique Values
... not allow pagination."
Implementation example in JavaScript:
const ITEMS_PER_PAGE = 1000;
const body = {
"size": 0, // Returning only aggregation results: https://www.elastic.co/guide/en/elasticsearch/reference/current/returning-only-agg-results.html
"aggs" : {
"langs"...
What are the differences between segment trees, interval trees, binary indexed trees and range trees
...h points fall within a given interval" queries.
Binary indexed tree stores items-count per index, and optimized for "how many items are there between index m and n" queries.
Performance / Space consumption for one dimension:
Segment tree - O(n logn) preprocessing time, O(k+logn) query time, O(n ...
How do you match only valid roman numerals with a regular expression?
...r problem (!): to do a "left trim" of remaining/residual roman number of a item list (HTML OL of type I or i). So, when there are remaining, I need to clean (like a trim function) with your regex at the beginning (left) of the item-text... But more simple: items never use M or C or L, so, do you hav...
How do I call one constructor from another in Java?
...in the same class, not from a subclass)? If yes how? And what could be the best way to call another constructor (if there are several ways to do it)?
...
Declare and Initialize String Array in VBA
...r_array)
Then you can do something static like this:
myStringArray = { item_1, item_2, ... }
Or something iterative like this:
Dim x
For x = 0 To size_of_your_array
myStringArray(x) = data_source(x).Name
Next x
s...