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How long is the SHA256 hash?
...
you can use this select statement to test it: SELECT length(to_base64(unhex(sha2('say hello to my little friend',256)))) , it is always 44 whatever the length of original string is.
– DrAhmedJava
Apr 9 '...
Pretty-print C++ STL containers
...t print a delimiter after the final item
template<typename T, typename TChar = char, typename TCharTraits = std::char_traits<TChar> >
class pretty_ostream_iterator : public std::iterator<std::output_iterator_tag, void, void, void, void>
{
public:
typedef TChar char_type;
ty...
Merging two arrays in .NET
...ew[] { 1, 2, 3, 4, 5 };
var arr2 = new[] { 6, 7, 8, 9, 0 };
var arr = arr1.Union(arr2).ToArray();
Keep in mind, this will remove duplicates. If you want to keep duplicates, use Concat.
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im...
Convert Rows to columns using 'Pivot' in SQL Server
...9, 3, 87);
If your values are known, then you will hard-code the query:
select *
from
(
select store, week, xCount
from yt
) src
pivot
(
sum(xcount)
for week in ([1], [2], [3])
) piv;
See SQL Demo
Then if you need to generate the week number dynamically, your code will be:
DECLARE @c...
Why should hash functions use a prime number modulus?
...er of buckets. This is convenient and saves having to search around or pre-select a prime number of the right magnitude. So you rely on the hash function not to use even multipliers, which is generally a safe assumption. But you can still get occasional bad hashing behaviours based on hash functions...
What are the differences between struct and class in C++?
...ate by
default. Members of a class defined
with the keywords struct or union
are public by default.
Additional difference: the keyword class can be used to declare template parameters, while the struct keyword cannot be so used.
...
Clang vs GCC for my Linux Development project
...4/include/g++-v4/ostream:112: note: candidates are: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>& (*)(std::basic_ostream<_CharT, _Traits>&)) [with _CharT = char, _Traits = std::char_...
How to do a regular expression replace in MySQL?
...ositions and perform substring substitution and extraction, respectively.
SELECT REGEXP_REPLACE('Stackoverflow','[A-Zf]','-',1,0,'c');
-- Output:
-tackover-low
DBFiddle Demo
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Why the switch statement cannot be applied on strings?
...however this might not be so easy for strings (considering run-time locale selection and so on). I suppose that such a thing would have to require constexpr cases, or add in unspecified behaviour (never a thing that we want to do).
– M.M
Jun 11 '15 at 23:37
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Verifying that a string contains only letters in C#
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This assumes a latin alphabet, where Char.IsLetter allows for non-latin alphabets.
– Paul van Brenk
Jul 28 '09 at 7:31
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