大约有 43,000 项符合查询结果（耗时：0.0215秒） [XML]
Try catch statements in C
...ou can simulate them to a degree with setjmp and longjmp calls.
static jmp_buf s_jumpBuffer;
void Example() {
if (setjmp(s_jumpBuffer)) {
// The longjmp was executed and returned control here
printf("Exception happened here\n");
} else {
// Normal code execution starts here
Te...
How to make rpm auto install dependencies
...
No, this will not work unless libtest1-1.0-1.x86_64.rpm is in a repository elsewhere, or both packages are specified on the command line like "rpm -i" would require. I just verified this on yum 3.4.3 (Fedora 18). Transcript here showing that it goes to the updates repo for...
What is the most efficient string concatenation method in python?
...iven the test case from mkoistinen's answer, having strings
domain = 'some_really_long_example.com'
lang = 'en'
path = 'some/really/long/path/'
The contenders are
f'http://{domain}/{lang}/{path}' - 0.151 µs
'http://%s/%s/%s' % (domain, lang, path) - 0.321 µs
'http://' + domain + '/' + lang ...
Django select only rows with duplicate field values
...values('name')
.annotate(Count('id'))
.order_by()
.filter(id__count__gt=1)
This is as close as you can get with Django. The problem is that this will return a ValuesQuerySet with only name and count. However, you can then use this to construct a regula...
Ruby: require vs require_relative - best practice to workaround running in both Ruby =1.
... this post.
https://github.com/appoxy/aws/blob/master/lib/awsbase/require_relative.rb
unless Kernel.respond_to?(:require_relative)
module Kernel
def require_relative(path)
require File.join(File.dirname(caller[0]), path.to_str)
end
end
end
This allows you to use require_relati...
How to run code when a class is subclassed? [duplicate]
...on2 you would define the metaclass of a class with
class SuperClass:
__metaclass__ = Watcher
where Watcher is a subclass of type.
In Python3 the syntax has been changed to
class SuperClass(metaclass=Watcher)
Both are equivalent to
Superclass = Watcher(name, bases, clsdict)
where in t...
Finding the source code for built-in Python functions?
... particular module or function is implemented in you can usually print the __file__ attribute. Alternatively, you may use the inspect module, see the section Retrieving Source Code in the documentation of inspect.
For built-in classes and methods this is not so straightforward since inspect.getfile...
Pickle or json?
...ccf1b3fa91f4399902bb534/raw/03e8dbab11b5605bc572bc117c8ac34cfa959a70/pickle_vs_json.py
python pickle_vs_json.py
Results with python 2.7 on a decent 2015 Xeon processor:
Dir Entries Method Time Length
dump 10 JSON 0.017 1484510
load 10 JSON 0.375 -
dump 10 Pickle 0.011 ...
How to import a module given the full path?
...
For Python 3.5+ use:
import importlib.util
spec = importlib.util.spec_from_file_location("module.name", "/path/to/file.py")
foo = importlib.util.module_from_spec(spec)
spec.loader.exec_module(foo)
foo.MyClass()
For Python 3.3 and 3.4 use:
from importlib.machinery import SourceFileLoader
fo...
Clean code to printf size_t in C++ (or: Nearest equivalent of C99's %z in C++)
I have some C++ code that prints a size_t :
9 Answers
9
...