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Why should hash functions use a prime number modulus?
...ame from. Similar function is Rabin fingerprint from Rabin-Karp algorithm (1981) but K&R (1978) predates that.
– bain
Apr 23 '17 at 10:32
...
PreparedStatement IN clause alternatives?
...olumn FROM my_table WHERE search_column = ?, execute it for each value and UNION the results client-side. Requires only one prepared statement. Slow and painful.
Prepare SELECT my_column FROM my_table WHERE search_column IN (?,?,?) and execute it. Requires one prepared statement per size-of-IN-list....
Why does Clojure have “keywords” in addition to “symbols”?
...t constructs are needed. Couldn't Clojure have created something with the union of the capabilities of both Keyword and Symbol?
– user73774
Oct 16 '09 at 19:57
25
...
LINQ to read XML
...=>
new string[]{ l.Attribute("name").Value }
.Union(
l.Descendants("level2")
.Select(l2=>" " + l2.Attribute("name").Value)
)
);
foreach (var lv in lvs)
{
result.AppendLine(lv);
...
How do I convert between big-endian and little-endian values in C++?
...wap_endian(T u)
{
static_assert (CHAR_BIT == 8, "CHAR_BIT != 8");
union
{
T u;
unsigned char u8[sizeof(T)];
} source, dest;
source.u = u;
for (size_t k = 0; k < sizeof(T); k++)
dest.u8[k] = source.u8[sizeof(T) - k - 1];
return dest.u;
}
us...
Can a C# class inherit attributes from its interface?
...e = typeof(T);
return type.GetCustomAttributes(attributeType, true).
Union(type.GetInterfaces().
SelectMany(interfaceType => interfaceType.GetCustomAttributes(attributeType, true))).
Distinct().Cast<T>();
}
...
Is there a REAL performance difference between INT and VARCHAR primary keys?
...ue. One of my biggest databases has entries for Yugoslavia and the Soviet Union. I'm glad they're not primary keys.
– Paul Tomblin
Dec 1 '08 at 21:39
8
...
What's the best way to join on the same table twice?
...
You could use UNION to combine two joins:
SELECT Table1.PhoneNumber1 as PhoneNumber, Table2.SomeOtherField as OtherField
FROM Table1
JOIN Table2
ON Table1.PhoneNumber1 = Table2.PhoneNumber
UNION
SELECT Table1.PhoneNumber2 as Phon...
PHP: merge two arrays while keeping keys instead of reindexing?
... Be VERY careful with this! The + operator is not an addition, it's a union. If the keys don't overlap then all is good, but if they do...
– GordonM
May 3 '12 at 15:46
3
...
PHP prepend associative array with literal keys?
...hat contains the new key-value pair at the beginning of the array with the union operator +. The outcome is an entirely new array though and creating the new array has O(n) complexity.
The syntax is below.
$new_array = array('new_key' => 'value') + $original_array;
Note: Do not use array_merg...