大约有 40,000 项符合查询结果（耗时：0.0441秒） [XML]
What does $_ mean in PowerShell?
...
This is the variable for the current value in the pipe line, which is called $PSItem in Powershell 3 and newer.
1,2,3 | %{ write-host $_ }
or
1,2,3 | %{ write-host $PSItem }
For example in the above code the %{} block is called for every value in the array. The $_ or $PSItem variable ...
Forced naming of parameters in Python
...(10, forcenamed=20)
10 20
>>> foo(10, 20)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: foo() takes exactly 1 positional argument (2 given)
This can also be combined with **kwargs:
def foo(pos, *, forcenamed, **kwargs):
...
What are the applications of binary trees?
...ningless - they are not a data structure, but a family of data structures, all with different performance characteristics. While it is true that unbalanced binary trees perform much worse than self-balancing binary trees for searching, there are many binary trees (such as binary tries) for which "b...
How to Create Deterministic Guids
...correct and has errata that fixes the C code (rfc-editor.org/errata_search.php?rfc=4122&eid=1352). If this implementation is not fully compliant with RFC4122 and its errata, please provide further details; I would like to make it follow the standard.
– Bradley Grainger
...
How can I filter a date of a DateTimeField in Django?
...
Much better than all of the other answers here, thanks!
– Kin
Jan 6 '14 at 17:06
...
Django select only rows with duplicate field values
... syntax is also how Django interprets you wanting to do a join. So, essentially when you try to filter on that, Django thinks you're trying to do a join with count which obviously doesn't exist. The fix is to specify a name for your annotation result, i.e. annotate(mycount=Count('id')) and then filt...
Which is faster: while(1) or while(2)?
...
mov rbp, rsp
.seh_setframe rbp, 0
sub rsp, 32
.seh_stackalloc 32
.seh_endprologue
call __main
.L2:
jmp .L2
.seh_endproc
.ident "GCC: (tdm64-2) 4.8.1"
With -O1:
.file "main.c"
.intel_syntax noprefix
.def __main; .scl 2; .type 32; .end...
Hidden features of C
I know there is a standard behind all C compiler implementations, so there should be no hidden features. Despite that, I am sure all C developers have hidden/secret tricks they use all the time.
...
How do I get the full path to a Perl script that is executing?
...me of the script during execution. I discovered that depending on how you call the script $0 varies and sometimes contains the fullpath+filename and sometimes just filename . Because the working directory can vary as well I can't think of a way to reliably get the fullpath+filename of the scr...
Can you find all classes in a package using reflection?
Is it possible to find all classes or interfaces in a given package? (Quickly looking at e.g. Package , it would seem like no.)
...