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How to query as GROUP BY in django?
...eturning designation and dcount, what if i want to get other values of the table too?
– A.J.
Mar 5 '14 at 8:02
20
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What is “overhead”?
...uably more absurd) approach would be to post all of the inputs to some SQL table in an RDBMS. Then simply calling the SQL SUM function on that column of that table. This shifts our local memory overhead to some other server, and incurs network overhead and external dependencies on our execution. ...
Why should we typedef a struct so often in C?
...les, and enumeration constants).
C compilers maintain tags in a symbol
table that's conceptually if not
physically separate from the table
that holds all other names. Thus, it
is possible for a C program to have
both a tag and an another name with
the same spelling in the same scope.
...
Is there a software-engineering methodology for functional programming? [closed]
... bases of what it takes to build real systems, while maintaining minimal mutable state in a highly controlled fashion. I'm toying with building Pong and Tetris in a FRelP style (excuse the strange initialism, but there is already another more popular FRP: Functional Reactive Programming).
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Android accelerometer accuracy (Inertial navigation)
...Xr, Yr, and Zr. Without the rotation data, you don't have enough data to establish a vector unless you assume the device never changes it's attitude, which would be pretty limiting. No one reads the TOS anyway.
Oh, and you know that INS drifts with the rotation of the earth, right? So there's that ...
hexadecimal string to byte array in python
...hex(hex_string)
bytearray(b'\xde\xad\xbe\xef')
Note that bytes is an immutable version of bytearray.
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How do function pointers in C work?
...eritance in C.
Let's say we want to make a subclass of String, say an ImmutableString. In order to make the string immutable, the set method will not be accessible, while maintaining access to get and length, and force the "constructor" to accept a char*:
typedef struct ImmutableString_Struct* Imm...
Is “ ” a replacement of “ ”?
... the same except for the fact that the latter does not need another lookup table to find its actual value. The lookup table is called a DTD, by the way.
You can read more about character entity references in the offical W3C documents.
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How to Test a Concern in Rails
...p the database accordingly (because your dummy class won't have a database table backing it). Moreover, you'll want to not only test the concern but also test the concern's behavior inside your model specs.
So why not kill two birds with one stone? By using RSpec's shared example groups, you can te...