大约有 40,000 项符合查询结果（耗时：0.0432秒） [XML]
Linq to Sql: Multiple left outer joins
...
This may be cleaner (you dont need all the into statements):
var query =
from order in dc.Orders
from vendor
in dc.Vendors
.Where(v => v.Id == order.VendorId)
.DefaultIfEmpty()
from status
in dc.Status
.Where(...
Sibling package imports
...ks well for private scripts, but there has been several improvements
Installing the package (in a virtualenv or not) will give you what you want, though I would suggest using pip to do it rather than using setuptools directly (and using setup.cfg to store the metadata)
Using the -m flag and runnin...
How to work with complex numbers in C?
...h:
creal(z1): get the real part (for float crealf(z1), for long double creall(z1))
cimag(z1): get the imaginary part (for float cimagf(z1), for long double cimagl(z1))
Another important point to remember when working with complex numbers is that functions like cos(), exp() and sqrt() must be repl...
What is “:-!!” in C code?
...sizeof(struct { int: -!!(e); }))
(e): Compute expression e.
!!(e): Logically negate twice: 0 if e == 0; otherwise 1.
-!!(e): Numerically negate the expression from step 2: 0 if it was 0; otherwise -1.
struct{int: -!!(0);} --> struct{int: 0;}: If it was zero, then we declare a struct with an an...
Use find command but exclude files in two directories
...k for files with the name ending in _peaks.bed
! -path "./tmp/*" - Exclude all results whose path starts with ./tmp/
! -path "./scripts/*" - Also exclude all results whose path starts with ./scripts/
Testing the Solution:
$ mkdir a b c d e
$ touch a/1 b/2 c/3 d/4 e/5 e/a e/b
$ find . -type f ! -p...
Python Infinity - Any caveats?
...involving inf:
>>> 0 * float("inf")
nan
Note that you will normally not get an inf value through usual arithmetic calculations:
>>> 2.0**2
4.0
>>> _**2
16.0
>>> _**2
256.0
>>> _**2
65536.0
>>> _**2
4294967296.0
>>> _**2
1.84467440737...
How do you 'redo' changes after 'undo' with Emacs?
...ven a navigation command such as C-f) after a sequence of undo operations, all the undos are pushed on to the operation stack. So the next undo undoes the last command. Suppose you do have an operation sequence that looks like this:
Insert "foo"
Insert "bar"
Insert "I love spam"
Now, you undo....
Why does GCC generate such radically different assembly for nearly the same C code?
...e(). I'll spare you the assembly, but it is identical - register names and all.
Step 2: Mathematical reduction: x + (y ^ x) = y
sign can only take one of two values, 0 or 0x80000000.
When x = 0, then x + (y ^ x) = y then trivial holds.
Adding and xoring by 0x80000000 is the same. It flips the sign...
What is time_t ultimately a typedef to?
...IX-compliant systems implement the time_t type as a signed
integer (typically 32 or 64 bits wide)
which represents the number of seconds
since the start of the Unix epoch:
midnight UTC of January 1, 1970 (not
counting leap seconds). Some systems
correctly handle negative time values,
w...
Node.js / Express.js - How does app.router work?
...use is app.use() . When the middleware is being executed, it will either call the next middleware by using next() or make it so no more middleware get called. That means that the order in which I place my middleware calls is important, because some middleware depends on other middleware, and some...