大约有 47,000 项符合查询结果（耗时：0.0386秒） [XML]
Rank function in MySQL
...k of customers. Here I am adding the corresponding ANSI standard SQL query for my requirement. Please help me to convert it to MySQL .
...
What are type lambdas in Scala and what are their benefits?
...g with higher-kinded types.
Consider a simple example of defining a monad for the right projection of Either[A, B]. The monad typeclass looks like this:
trait Monad[M[_]] {
def point[A](a: A): M[A]
def bind[A, B](m: M[A])(f: A => M[B]): M[B]
}
Now, Either is a type constructor of two argu...
JavaScript for detecting browser language preference [duplicate]
...vascript at all. (Probably why @anddoutoi states he can't find a reference for it that doesn't involve server side.)
I have coded a workaround: I've knocked up a google app engine script at http://ajaxhttpheaders.appspot.com that will return you the HTTP request headers via JSONP.
(Note: this is a...
how to create a file name with the current date & time in python?
...(answers your question) of getting a string with the current time and date format you specify:
import time
timestr = time.strftime("%Y%m%d-%H%M%S")
print timestr
yields:
20120515-155045
so your filename could append or use this string.
...
Random string generation with upper case letters and digits
...n one line:
''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(N))
or even shorter starting with Python 3.6 using random.choices():
''.join(random.choices(string.ascii_uppercase + string.digits, k=N))
A cryptographically more secure version; see https://stackoverflow....
What's the bad magic number error?
...c' -delete
If they are not yours, you'll have to either get the py files for re-compilation, or an interpreter that can run the pyc files with that particular magic value.
One thing that might be causing the intermittent nature. The pyc that's causing the problem may only be imported under certai...
How do I concatenate strings and variables in PowerShell?
..., yes "... $name ..." will work all the same, but in the original question for which this answer addresses, the question is how to access object properties. so if $name.id -eq 42 then "... $name.id ..." would not work like you want because it would render like ... @{id=42}.id ... instead of the desi...
How to specify different Debug/Release output directories in QMake .pro file
...o file to behave: it simply starts qmake and then make in the build folder for your target's chosen configuration.
If you wish to create these folders and perform the two (or more) builds in them, you'll need a top-level makefile, possibly created from a top-level project file via qmake.
It's not ...
Get a random item from a JavaScript array [duplicate]
... var items = ["a","e","i","o","u"] var objResults = {} for(var i = 0; i < 1000000; i++){ var randomElement = items[Math.floor(Math.random()*items.length)] if (objResults[randomElement]){ objResults[randomElement]++ }else{ ...
Django database query: How to get object by id?
...
If you want to get an object, using get() is more straightforward:
obj = Class.objects.get(pk=this_object_id)
share
|
improve this answer
|
follow
...