大约有 47,000 项符合查询结果（耗时：0.0496秒） [XML]
What is Func, how and when is it used
...ied to any particular functionality.
For example, consider the Enumerable.Select extension method.
The pattern is: for every item in a sequence, select some value from that item (e.g., a property) and create a new sequence consisting of these values.
The placeholder is: some selector function tha...
Which machine learning classifier to choose, in general? [closed]
...
Model selection using cross validation may be what you need.
Cross validation
What you do is simply to split your dataset into k non-overlapping subsets (folds), train a model using k-1 folds and predict its performance using the...
How to remove selected commit log entries from a Git repository while keeping their changes?
I would like to remove selected commit log entries from a linear commit tree, so that the entries do not show in the commit log.
...
iOS: How to store username/password within an app?
... 3 right-click on frameworks folder and add existing framework. In Xcode 4 select your project, then select target, go to Build Phases tab and click + under Link Binary With Files) and KeychainItemWrapper .h & .m files into your project, #import the .h file wherever you need to use keychain and ...
How do I change db schema to dbo
...which will generate a set of ALTER sCHEMA statements for all your talbes:
SELECT 'ALTER SCHEMA dbo TRANSFER ' + TABLE_SCHEMA + '.' + TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'jonathan'
You then have to copy and run the statements in query analyzer.
Here's an older script t...
What is the use of the square brackets [] in sql statements?
...
sql also uses square brackets in the like-operator of a select query to limit results using regular expressions. codeproject.com/Articles/33941/SQL-LIKE-Operator
– Jens Frandsen
Sep 4 '13 at 18:49
...
How to do SELECT COUNT(*) GROUP BY and ORDER BY in Django?
...lvaro has answered the Django's direct equivalent for GROUP BY statement:
SELECT actor, COUNT(*) AS total
FROM Transaction
GROUP BY actor
is through the use of values() and annotate() methods as follows:
Transaction.objects.values('actor').annotate(total=Count('actor')).order_by()
However ...
Standard alternative to GCC's ##__VA_ARGS__ trick?
...ine REST_HELPER_TWOORMORE(first, ...) , __VA_ARGS__
#define NUM(...) \
SELECT_10TH(__VA_ARGS__, TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE,\
TWOORMORE, TWOORMORE, TWOORMORE, TWOORMORE, ONE, throwaway)
#define SELECT_10TH(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, ...) a10
int
main...
How to assign an exec result to a sql variable?
...esultForPos INT
EXEC @ResultForPos = storedprocedureName 'InputParameter'
SELECT @ResultForPos
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What's the fastest way to do a bulk insert into Postgres?
...200, 300]),
UNNEST(ARRAY['a', 'b', 'c'])
);
without VALUES using subselect with additional existance check:
INSERT INTO tablename (fieldname1, fieldname2, fieldname3)
SELECT * FROM (
SELECT UNNEST(ARRAY[1, 2, 3]),
UNNEST(ARRAY[100, 200, 300]),
UNNEST(ARRAY['a', 'b...