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Django select only rows with duplicate field values
...ne these into a single query:
Literal.objects.filter(name__in=dups)
The extra call to .values('name') after the annotate call looks a little strange. Without this, the subquery fails. The extra values tricks the ORM into only selecting the name column for the subquery.
...
Call Go functions from C
... as "Callbacks rock!".
fmt.Printf("%s: %d / %d (%3.2f%%)\n", userdata.(string), current, total, fc / ft)
return 0
}
This all looks a lot more complicated than it is. The call order has not changed as opposed to our previous example, but we get two extra calls at the end of the chain:
The ...
Python str vs unicode types
...unicode instead of str , as both of them seem to be able to hold Unicode strings. Is there any special reason apart from being able to set Unicode codes in unicode strings using the escape char \ ?:
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What’s the best way to check if a file exists in C++? (cross platform)
...on in the stream:
#include <fstream>
bool checkExistence(const char* filename)
{
ifstream Infield(filename);
return Infield.good();
}
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Python strftime - date without leading 0?
... 2014'
And as of python3.6, this can be expressed as an inline formatted string:
Python 3.6.0a2 (v3.6.0a2:378893423552, Jun 13 2016, 14:44:21)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import datetime...
How to get the number of Characters in a String?
How can I get the number of characters of a string in Go?
7 Answers
7
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How do I get the path of a process in Unix / Linux
...swers were specific to linux.
If you need also unix, then you need this:
char * getExecPath (char * path,size_t dest_len, char * argv0)
{
char * baseName = NULL;
char * systemPath = NULL;
char * candidateDir = NULL;
/* the easiest case: we are in linux */
size_t buff_len;
...
What is the most efficient/elegant way to parse a flat table into a tree?
... sets (sometimes referred to as Modified Pre-order Tree Traversal) you can extract the entire tree structure or any subtree within it in tree order with a single query, at the cost of inserts being more expensive, as you need to manage columns which describe an in-order path through thee tree struct...
How can I convert String to Int?
...lse, but for noobish people what 'out x' does is set the value of x to the string-cast-as-integer, if the casting is successful. I.e. in this case, x = 0 if the string has any non-integer characters, or x = value of string-as-integer otherwise. So the neat thing is this is one short expression which...
How to insert a character in a string at a certain position?
I'm getting in an int with a 6 digit value. I want to display it as a String with a decimal point (.) at 2 digits from the end of int . I wanted to use a float but was suggested to use String for a better display output (instead of 1234.5 will be 1234.50 ). Therefore, I need a function t...