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What's the difference between console.dir and console.log?
...ozilla.org/en-US/docs/Web/API/Console/log
– loneshark99
Feb 20 '18 at 18:18
13
@loneshark99 actua...
Should I use 'has_key()' or 'in' on Python dicts?
...but also in performance, e.g.:
$ python -mtimeit -s'd=dict.fromkeys(range(99))' '12 in d'
10000000 loops, best of 3: 0.0983 usec per loop
$ python -mtimeit -s'd=dict.fromkeys(range(99))' 'd.has_key(12)'
1000000 loops, best of 3: 0.21 usec per loop
While the following observation is not always tru...
Pragma in define macro
...
If you're using c99 or c++0x there is the pragma operator, used as
_Pragma("argument")
which is equivalent to
#pragma argument
except it can be used in macros (see section 6.10.9 of the c99 standard, or 16.9 of the c++0x final committee...
Why does the C preprocessor interpret the word “linux” as the constant “1”?
...line options:
gcc -std=c90 -pedantic ... # or -std=c89 or -ansi
gcc -std=c99 -pedantic
gcc -std=c11 -pedantic
See the gcc manual for more details.
gcc will be phasing out these definitions in future releases, so you shouldn't write code that depends on them. If your program needs to know whether...
What is the difference between typeof and instanceof and when should one be used vs. the other?
...alse
true instanceof Boolean; // false
typeof true == 'boolean'; // true
99.99 instanceof Number; // false
typeof 99.99 == 'number'; // true
function() {} instanceof Function; // true
typeof function() {} == 'function'; // true
Use instanceof for complex built in types:
/regularexpression/ ins...
What is the printf format specifier for bool?
Since ANSI C99 there is _Bool or bool via stdbool.h . But is there also a printf format specifier for bool?
8 Answer...
Standard alternative to GCC's ##__VA_ARGS__ trick?
There is a well-known problem with empty args for variadic macros in C99.
10 Answers
...
Matplotlib: “Unknown projection '3d'” error
...irst off, I think mplot3D worked a bit differently in matplotlib version 0.99 than it does in the current version of matplotlib.
Which version are you using? (Try running: python -c 'import matplotlib; print matplotlib."__version__")
I'm guessing you're running version 0.99, in which case you'll n...
Modulo operation with negative numbers
...
C99 requires that when a/b is representable:
(a/b) * b + a%b shall equal a
This makes sense, logically. Right?
Let's see what this leads to:
Example A. 5/(-3) is -1
=> (-1) * (-3) + 5%(-3) = 5
This can only happen i...
Difference between a Structure and a Union
...
union foo x;
x.a = 3;
x.b = 'c';
printf("%i, %i\n", x.a, x.b);
prints
99, 99
Why are the two values the same? Because the last 3 bytes of the int 3 are all zero, so it's also read as 99. If we put in a larger number for x.a, you'll see that this is not always the case:
union foo x;
x.a = 387...