大约有 19,000 项符合查询结果（耗时：0.0429秒） [XML]
How to select a single field for all documents in a MongoDB collection?
...uery. In the result set, only the item and qty fields and, by default, the _id field return in the matching documents.
db.inventory.find( { type: 'food' }, { item: 1, qty: 1 } )
In this example from the folks at Mongo, the returned documents will contain only the fields of item, qty, and _id.
Thus...
How to find the JVM version from a program?
...version "12" "1.8.0_201" "1.5.0_22" Java Runtime Environment version, which may be interpreted as a Runtime.Version
java.version.date "2019-03-19" ...
Can “list_display” in a Django ModelAdmin display attributes of ForeignKey fields?
...ion, you can do look ups like:
class UserAdmin(admin.ModelAdmin):
list_display = (..., 'get_author')
def get_author(self, obj):
return obj.book.author
get_author.short_description = 'Author'
get_author.admin_order_field = 'book__author'
...
What does pylint's “Too few public methods” message mean
...they hold.
If your class looks like this:
class MyClass(object):
def __init__(self, foo, bar):
self.foo = foo
self.bar = bar
Consider using a dictionary or a namedtuple instead. Although if a class seems like the best choice, use it. pylint doesn't always know what's best.
D...
Flattening a shallow list in Python [duplicate]
...ndexable sequence, consider itertools.chain and company.
>>> list_of_menuitems = [['image00', 'image01'], ['image10'], []]
>>> import itertools
>>> chain = itertools.chain(*list_of_menuitems)
>>> print(list(chain))
['image00', 'image01', 'image10']
It will work...
What are the calling conventions for UNIX & Linux system calls (and user-space functions) on i386 an
...rameters for Linux system call are passed using registers. %eax for syscall_number. %ebx, %ecx, %edx, %esi, %edi, %ebp are used for passing 6 parameters to system calls.
The return value is in %eax. All other registers (including EFLAGS) are preserved across the int $0x80.
I took following snipp...
Best practices for reducing Garbage Collector activity in Javascript
...
Regarding "premature optimization is the root of all evil": Understand. Don't just follow blindly. In certain scenarios, such as game and multimedia programming, performance is paramount and you're going to have a lot of "hot" code. So yeah, you're going to have to ...
Resolve build errors due to circular dependency amongst classes
...riting a compiler. And you see code like this.
// file: A.h
class A {
B _b;
};
// file: B.h
class B {
A _a;
};
// file main.cc
#include "A.h"
#include "B.h"
int main(...) {
A a;
}
When you are compiling the .cc file (remember that the .cc and not the .h is the unit of compilation), you ne...
How to combine two or more querysets in a Django view?
... pagination on the search result list, I would like to use a generic object_list view to display the results. But to do that, I have to merge 3 querysets into one.
...
how to break the _.each function in underscore.js
I'm looking for a way to stop iterations of underscore.js _.each() method, but can't find the solution. jQuery .each() can break if you do return false .
...