大约有 40,000 项符合查询结果（耗时：0.0539秒） [XML]
What are the main performance differences between varchar and nvarchar SQL Server data types?
...
What about index size, memory usage etc? I assume you always use int when you could use tinyint too "just in case"?
– gbn
Jul 9 '10 at 7:02
...
How to determine SSL cert expiration date from a PEM encoded certificate?
...s in order of their expiration, most recently expiring first.
for pem in /etc/ssl/certs/*.pem; do
printf '%s: %s\n' \
"$(date --date="$(openssl x509 -enddate -noout -in "$pem"|cut -d= -f 2)" --iso-8601)" \
"$pem"
done | sort
Sample output:
2015-12-16: /etc/ssl/certs/Staat_der_Ned...
What is a mixin, and why are they useful?
...rMixin, Parent): pass and class NewChildN(NewBehaviorMixin, ChildN): pass, etc. (PS: Do you know a better way?)
– RayLuo
Oct 18 '16 at 0:57
|
...
Total memory used by Python process?
...tion that works for various operating systems, including Linux, Windows 7, etc.:
import os
import psutil
process = psutil.Process(os.getpid())
print(process.memory_info().rss) # in bytes
On my current Python 2.7 install with psutil 5.6.3, the last line should be
print(process.memory_info()[0...
Why 0 is true but false is 1 in the shell?
...l kinds of information about the failure - why it happened, how to fix it, etc. Having zero mean 'success' and non-zero mean failure lets you can check pretty easily for success, and investigate the particular error for more details if you want to. A lot of APIs and frameworks have a similar conve...
Extracting just Month and Year separately from Pandas Datetime column
...column'].dt.to_period('M')
You could also use D for Day, 2M for 2 Months etc. for different sampling intervals, and in case one has time series data with time stamp, we can go for granular sampling intervals such as 45Min for 45 min, 15Min for 15 min sampling etc.
...
How do the likely/unlikely macros in the Linux kernel work and what is their benefit?
...nch prediction does work. Taken branches are problematic for instruction-fetch and decode even when they're predicted perfectly. Some CPUs statically predict branches that aren't in their history table, usually with assume not-taken for forward branches. Intel CPUs don't work that way: they don't...
What is the difference between a field and a property?
...e can put logic in the Property also allows us to perform validation logic etc if we need it.
C# 3 has the possibly confusing notion of autoproperties. This allows us to simply define the Property and the C#3 compiler will generate the private field for us.
public class Person
{
private string _...
Polymorphism in C++
...hosen at runtime based on config files, command line switches, UI settings etc.,
implementation varied at runtime, such as for a state machine pattern.
When there's not a clear driver for run-time polymorphism, compile-time options are often preferable. Consider:
the compile-what's-called aspec...
What are inline namespaces for?
...; : my_special_vector<MyOtherType> {
// ...
};
// ...etc...
} // namespace std
This is perfectly valid code where the user supplies its own implementation of a vector for a set of type where she apparently knows a more efficient implementation than the one found in (her copy ...