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Django in / not in query
...
table1.objects.exclude(id__in=
table2.objects.filter(your_condition).values_list('id', flat=True))
The exclude function works like the Not operator you where asking for. The attribute flat = True tells to table2 query to return the value_list a...
How does the algorithm to color the song list in iTunes 11 work? [closed]
...table... looks like I reinvented the wheel a bit here)
convertToYUV[rawRGB_] :=
Module[{yuv},
yuv = {{0.299, 0.587, 0.114}, {-0.14713, -0.28886, 0.436},
{0.615, -0.51499, -0.10001}};
yuv . rawRGB
]
Next, I wrote a function to calculate color distance with the a...
Read file from line 2 or skip header row
...
Or use header_line = next(f).
– Samuel
Jan 6 '15 at 23:41
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Why use apparently meaningless do-while and if-else statements in macros?
...mi-colon. Should the user view code not needing one...
doSomething(1) ;
DO_SOMETHING_ELSE(2) // <== Hey? What's this?
doSomethingElseAgain(3) ;
This means the user expects the compiler to produce an error if the semi-colon is absent.
But the real real good reason is that at some time, the ma...
How do I install an R package from source?
...hen use install.packages() and set the repos=NULL:
install.packages(path_to_file, repos = NULL, type="source")
Where path_to_file would represent the full path and file name:
On Windows it will look something like this: "C:\\RJSONIO_0.2-3.tar.gz".
On UNIX it will look like this: "/home/blah/R...
C default arguments
.... Define a companion struct:
typedef struct {
int i;
double x;
} f_args;
Rename your function f_base, and define a wrapper function that sets defaults and calls
the base:
double var_f(f_args in){
int i_out = in.i ? in.i : 8;
double x_out = in.x ? in.x : 3.14;
return f_base(i_...
如何获取IE (控件)的所有链接（包括Frameset, iframe） - 其他 - 清泛IT社...
来源：新浪博客
IE 顶层 body 节点通过IHTMLElement->get_all 方法无法获取iframe 里面的节点列表：
CComPtr<IHTMLElement> body;
...
CComPtr<IDispatch> spDispCollection;
body->get_all(&spDispCollection);复制代码所以要获取iframe/frame(frameset) ...
How do you 'redo' changes after 'undo' with Emacs?
...
To undo: C-_
To redo after a undo: C-g C-_
Type multiple times on C-_ to redo what have been undone by C-_
To redo an emacs command multiple times, execute your command then type C-xz and then type many times on z key to repea...
Calling a function of a module by using its name (a string)
...
Assuming module foo with method bar:
import foo
method_to_call = getattr(foo, 'bar')
result = method_to_call()
You could shorten lines 2 and 3 to:
result = getattr(foo, 'bar')()
if that makes more sense for your use case.
You can use getattr in this fashion on class insta...
Cleaner way to update nested structures
...ss, and an address in a person:
val addressZipCodeLens = Lens(
get = (_: Address).zipCode,
set = (addr: Address, zipCode: Int) => addr.copy(zipCode = zipCode))
val personAddressLens = Lens(
get = (_: Person).address,
set = (p: Person, addr: Address) => p.copy(address = addr)...