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mongodb count num of distinct values per field/key
Is there a query for calculating how many distinct values a field contains in DB.
5 Answers
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clang: how to list supported target architectures?
...d clang binaries may not correspond to the same version of LLVM.
However, for the sake of argument, let's say that you compiled both LLVM and Clang yourself or that you're otherwise happy to accept your LLVM binaries as good enough:
llc --version will give a list of all architectures it supports....
How to add an extra column to a NumPy array
...
I think a more straightforward solution and faster to boot is to do the following:
import numpy as np
N = 10
a = np.random.rand(N,N)
b = np.zeros((N,N+1))
b[:,:-1] = a
And timings:
In [23]: N = 10
In [24]: a = np.random.rand(N,N)
In [25]: %ti...
C/C++获取Windows的CPU、内存、硬盘使用率 - C/C++ - 清泛网 - 专注C/C++及内核技术
...且每次触发后自动设置为nonsignaled
while (true)
{
WaitForSingleObject(hEvent, 1000);
res = GetSystemTimes(&idleTime, &kernelTime, &userTime);
__int64 idle = CompareFileTime(preidleTime, idleTime);
__int64 kernel = CompareFileTime(prekernelTime, kernelTime);
__int64 u...
What is a method that can be used to increment letters?
... it depends on what you want out of it. The solution above will return '{' for the character after 'z', and this is the character after 'z' in ASCII, so it could be the result you're looking for depending on what your use case is.
Unique string generator
(Updated 2019/05/09)
Since this answer h...
Comparing mongoose _id and strings
...method, if you wish to store a stringified version of the ObjectID in JSON format, or a cookie.
If you use ObjectID = require("mongodb").ObjectID (requires the mongodb-native library) you can check if results.userId is a valid identifier with results.userId instanceof ObjectID.
Etc.
...
Filter by property
...del.objects)
But it's better to use a list comprehension:
filtered = [x for x in MyModel.objects if x.myproperty()]
or even better, a generator expression:
filtered = (x for x in MyModel.objects if x.myproperty())
sha...
jQuery find events handlers registered with an object
...of jQuery 1.8, the event data is no longer available from the "public API" for data. Read this jQuery blog post. You should now use this instead:
jQuery._data( elem, "events" );
elem should be an HTML Element, not a jQuery object, or selector.
Please note, that this is an internal, 'private' s...
Getting visitors country from their IP
...;
if ($deep_detect) {
if (filter_var(@$_SERVER['HTTP_X_FORWARDED_FOR'], FILTER_VALIDATE_IP))
$ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
if (filter_var(@$_SERVER['HTTP_CLIENT_IP'], FILTER_VALIDATE_IP))
$ip = $_SERVER['HTTP_CLIENT_IP'];
...
How can I link to a specific glibc version?
...blog post Linking to Older Versioned Symbols (glibc), it is possible to to force any symbol to be linked against an older one so long as it is valid by using the the same .symver pseudo-op that is used for defining versioned symbols in the first place. The following example is excerpted from the bl...