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C++ performance challenge: integer to std::string conversion
... val /= 10;
}
return s;
}
This will blow up on systems that disallow unaligned memory accesses (in which case, the first unaligned assignment via *(short*) would cause a segfault), but should work very nicely otherwise.
One important thing to do is to minimize the use of std::string. (I...
How to save an image to localStorage and display it on the next page?
So, basically, I need to upload a single image, save it to localStorage, then display it on the next page.
7 Answers
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Reading specific lines only
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with linecache.getlin('some_file', 4) I get the 4th line, not the 5th.
– Juan
Dec 11 '14 at 18:14
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Linq to Entities - SQL “IN” clause
...sing LINQ, one uses query syntax and the other uses method syntax. Essentially, they are the same and could be used interchangeably depending on your preference:
Query Syntax:
var selected = from u in users
where new[] { "Admin", "User", "Limited" }.Contains(u.User_Rights)
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Generating a random password in php
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Security warning: rand() is not a cryptographically secure pseudorandom number generator. Look elsewhere for generating a cryptographically secure pseudorandom string in PHP.
Try this (use strlen instead of count, because count on a string is always 1):
function random...
Programmatically get the version number of a DLL
Is it possible to get the version number programmatically from any .NET DLL?
10 Answers
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How do I view the list of functions a Linux shared library is exporting?
...AL DEFAULT UND
1: 00000000 0 FUNC GLOBAL DEFAULT UND pthread_mutex_unlock@GLIBC_2.0 (4)
2: 00000000 0 FUNC GLOBAL DEFAULT UND pthread_mutex_destroy@GLIBC_2.0 (4)
3: 00000000 0 NOTYPE WEAK DEFAULT UND _ITM_deregisterTMCloneTable
4: 00000000 0 FUNC ...
Where does PostgreSQL store the database?
...here the data directory is, use this query.
show data_directory;
To see all the run-time parameters, use
show all;
You can create tablespaces to store database objects in other parts of the filesystem. To see tablespaces, which might not be in that data directory, use this query.
SELECT * FRO...
What is the maximum value for an int32?
...bout 1 billion. One of the 32 bits is used for sign, so the max value is really only 2^31, which is about twice the amount you get for 2^(3*10): 2 billion.
– 16807
Dec 3 '13 at 22:24
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Calling shell functions with xargs
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Exporting the function should do it (untested):
export -f echo_var
seq -f "n%04g" 1 100 | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
You can use the builtin printf instead of the external seq:
printf "n%04g\n" {1..100} | xargs -n 1 -P 10 -I {} bash -c 'echo_var "$@"' _ {}
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