大约有 40,000 项符合查询结果（耗时：0.0424秒） [XML]
How do I check if there are duplicates in a flat list?
...6]), set([2, 3]))
"""
return reduce(
lambda (u, d), o : (u.union([o]), d.union(u.intersection([o]))),
a_list,
(set(), set()))
if __name__ == "__main__":
import doctest
doctest.testmod()
From there you can test unicity by checking whether the second element ...
How can you represent inheritance in a database?
...is is how you would have to query all the policies regardless of the type:
SELECT date_issued, other_common_fields, 'MOTOR' AS type
FROM policies_motor
UNION ALL
SELECT date_issued, other_common_fields, 'PROPERTY' AS type
FROM policies_property;
Note how adding new subtypes woul...
Why use the SQL Server 2008 geography data type?
...tance < 500 * 1609.344
orderby distance
select f;
return q1.FirstOrDefault();
}
Then there is a very good reason to use Geography.
Explanation of spatial within Entity Framework.
Updated with Creating High Performance Spatial Databases
As I noted on Noe...
Haskell Type vs Data Constructor
...nstructed in nearly any language", says Wikipedia. :) In e.g. C/++, that's unions, with a tag discipline. :)
– Will Ness
Aug 17 '13 at 20:38
5
...
Search an Oracle database for tables with specific column names?
...
To find all tables with a particular column:
select owner, table_name from all_tab_columns where column_name = 'ID';
To find tables that have any or all of the 4 columns:
select owner, table_name, column_name
from all_tab_columns
where column_name in ('ID', 'FNAME', ...
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign
...te definition in the XML and change it manually.
Remove primary keys from select lists in table adapters if they are not related to the data being returned.
Run your query in SQL Management Studio and ensure there are not duplicate records being returned. Duplicate records can generate duplicate p...
The opposite of Intersect()
...
This code enumerates each sequence only once and uses Select(x => x) to hide the result to get a clean Linq-style extension method. Since it uses HashSet<T> its runtime is O(n + m) if the hashes are well distributed. Duplicate elements in either list are omitted.
publi...
Is short-circuiting logical operators mandated? And evaluation order?
... function, at least one of the arguments needs to be a class (or struct or union) or an enum, or a reference to one of those. Being POD means that you can use memcpy on it.
– Derek Ledbetter
Mar 12 '09 at 21:45
...
C char array initialization
...y way at any time in the program, provided they are members of a struct or union.
Example program:
#include <stdio.h>
struct ccont
{
char array[32];
};
struct icont
{
int array[32];
};
int main()
{
int cnt;
char carray[32] = { 'A', 66, 6*11+1 }; // 'A', 'B', 'C', '\0', '\0', ....
Pointer arithmetic for void pointer in C
...s arguments to
functions, return values from
functions, and members of unions.
So this means that printf("%s", x) has the same meaning whether x has type char* or void*, but it does not mean that you can do arithmetic on a void*.
Editor's note: This answer has been edited to reflect the final...