大约有 16,000 项符合查询结果（耗时：0.0243秒） [XML]
Is there a difference between “==” and “is”?
...
is will return True if two variables point to the same object, == if the objects referred to by the variables are equal.
>>> a = [1, 2, 3]
>>> b = a
>>> b is a
True
>>> b == a
True
# Make a new copy of list `a` via the slice ...
Proper indentation for Python multiline strings
...P 257:
def trim(docstring):
if not docstring:
return ''
# Convert tabs to spaces (following the normal Python rules)
# and split into a list of lines:
lines = docstring.expandtabs().splitlines()
# Determine minimum indentation (first line doesn't count):
indent = sys...
Bash tool to get nth line from a file
...o be just as fast or faster. At least, it was (significantly) faster on my system when I tried it with NUM being 250000 on a file with half a million lines. YMMV, but I don't really see why it would.
– rici
Mar 25 '14 at 2:43
...
Render HTML to PDF in Django site
For my django powered site, I am looking for an easy solution to convert dynamic html pages to pdf.
8 Answers
...
How to do relative imports in Python?
...vel module, regardless of where the module is actually located on the file system.
In Python 2.6, they're adding the ability to reference modules relative to the main module. PEP 366 describes the change.
Update: According to Nick Coghlan, the recommended alternative is to run the module inside ...
Installing python module within code
...o make it clear to users that programmatic use of pip is not allowed.
Use sys.executable to ensure that you will call the same pip associated with the current runtime.
import subprocess
import sys
def install(package):
subprocess.check_call([sys.executable, "-m", "pip", "install", package])
...
Get __name__ of calling function's module in Python
...
Confronted with a similar problem, I have found that sys._current_frames() from the sys module contains interesting information that can help you, without the need to import inspect, at least in specific use cases.
>>> sys._current_frames()
{4052: <frame object at ...
Capture keyboardinterrupt in Python without try-except
...le signal, and wait forever using a threading.Event:
import signal
import sys
import time
import threading
def signal_handler(signal, frame):
print('You pressed Ctrl+C!')
sys.exit(0)
signal.signal(signal.SIGINT, signal_handler)
print('Press Ctrl+C')
forever = threading.Event()
forever.wai...
SQL DROP TABLE foreign key constraint
... could use this SQL (if you're on SQL Server 2005 and up):
SELECT *
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('Student')
and if there are any, with this statement here, you could create SQL statements to actually drop those FK relations:
SELECT
'ALTER TABLE [' + OBJECT_...
Better way to cast object to int
...here is an implicit conversion defined.
int.Parse()/int.TryParse() — For converting from a string of unknown format.
int.ParseExact()/int.TryParseExact() — For converting from a string in a specific format
Convert.ToInt32() — For converting an object of unknown type. It will use an explicit ...