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C++对象布局及多态探索之菱形结构虚继承 - C/C++ - 清泛网 - 专注C/C++及内核技术
...0则从C100和C101多重继承而来。
struct C041
{
C041() : c_(0x01) {}
virtual void foo() { c_ = 0x02; }
char c_;
};
struct C100 : public virtual C041
{
C100() : c_(0x02) {}
char c_;
};
struct C101 : public virtual C041
{
C101() : c_(0x03) {}
...
How do I pass extra arguments to a Python decorator?
... it needs to return another function which is the actual decorator:
def my_decorator(param):
def actual_decorator(func):
print("Decorating function {}, with parameter {}".format(func.__name__, param))
return function_wrapper(func) # assume we defined a wrapper somewhere
ret...
Append an object to a list in R in amortized constant time, O(1)?
... 2-element vector named c as is clearly intended!
– j_random_hacker
Dec 5 '11 at 16:45
7
So is th...
Python Flask, how to set content type
...
Try like this:
from flask import Response
@app.route('/ajax_ddl')
def ajax_ddl():
xml = 'foo'
return Response(xml, mimetype='text/xml')
The actual Content-Type is based on the mimetype parameter and the charset (defaults to UTF-8).
Response (and request) objects are docume...
Getting number of elements in an iterator in Python
...d work:
>>> iter = (i for i in range(50))
>>> sum(1 for _ in iter)
50
Although it does iterate through each item and count them, it is the fastest way to do so.
It also works for when the iterator has no item:
>>> sum(1 for _ in range(0))
0
Of course, it runs foreve...
How do I expire a PHP session after 30 minutes?
...a session timeout of your own. Both options mentioned by others (session.gc_maxlifetime and session.cookie_lifetime) are not reliable. I'll explain the reasons for that.
First:
session.gc_maxlifetime
session.gc_maxlifetime specifies the number of seconds after which data will be seen as 'garb...
sql “LIKE” equivalent in django query
...
Use __contains or __icontains (case-insensitive):
result = table.objects.filter(string__contains='pattern')
The SQL equivalent is
SELECT ... WHERE string LIKE '%pattern%';
...
Show the progress of a Python multiprocessing pool imap_unordered call?
... that's successfully doing a multiprocessing Pool set of tasks with a imap_unordered() call:
9 Answers
...
Input from the keyboard in command line application
...or how I set it up.
Usage from swift
let prompt: Prompt = Prompt(argv0: C_ARGV[0])
while (true) {
if let line = prompt.gets() {
print("You typed \(line)")
}
}
ObjC wrapper to expose libedit
#import <histedit.h>
char* prompt(EditLine *e) {
return "> ";
}
@implemen...
How to get the original value of an attribute in Rails
...
Before rails 5.1
Appending _was to your attribute will give you the previous value.
For rails 5.1+
Copied from Lucas Andrade's answer below: https://stackoverflow.com/a/50973808/9359123
Appending _was is deprecated in rails 5.1, now you should ap...