大约有 20,000 项符合查询结果（耗时：0.0449秒） [XML]
How to make a cross-module variable?
The __debug__ variable is handy in part because it affects every module. If I want to create another variable that works the same way, how would I do it?
...
How to override the [] operator in Python?
...
You need to use the __getitem__ method.
class MyClass:
def __getitem__(self, key):
return key * 2
myobj = MyClass()
myobj[3] #Output: 6
And if you're going to be setting values you'll need to implement the __setitem__ method too,...
Find current directory and file's directory [duplicate]
...ory a Python file is contained in, write this in that file:
import os
dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relativ...
RuntimeError on windows trying python multiprocessing
...l import (i.e. execute) the main module at start. You need to insert an if __name__ == '__main__': guard in the main module to avoid creating subprocesses recursively.
Modified testMain.py:
import parallelTestModule
if __name__ == '__main__':
extractor = parallelTestModule.ParallelExtrac...
What is a mixin, and why are they useful?
... and `==`,
but this class does NOT implement those methods."""
def __ne__(self, other):
return not (self == other)
def __lt__(self, other):
return self <= other and (self != other)
def __gt__(self, other):
return not self <= other
def __ge__(self, ot...
Difference between a theta join, equijoin and natural join
... yourself).
** I don't quite know what the result of SELECT * FROM table_expression; is. I know it is not a relation because, among other reasons, it can have columns with duplicate names or a column with no name. I know it is not a set because, among other reasons, the column order is significan...
How do I get the number of elements in a list?
...objects with a "size" in Python, in particular, have an attribute called ob_size, where the number of elements in the object is cached. So checking the number of objects in a list is very fast.
But if you're checking if list size is zero or not, don't use len - instead, put the list in a boolean co...
How to access outer class from an inner class?
...f):
return Outer.Inner(self)
class Inner(object):
def __init__(self, outer_instance):
self.outer_instance = outer_instance
self.outer_instance.somemethod()
def inner_method(self):
self.outer_instance.anothermethod()
...
【解决】scrapyd启动job时报错：exceptions.TypeError: __init__() got an ...
【解决】scrapyd启动job时报错：exceptions.TypeError: __init__() got an unexpected keyword argument '_job'进入项目spiders目录, 修改 spider py 文件（你自己的spider的主文件）：def __init__(self):改为：def __init__(self, *args, **kwargs):最后不要忘了重新部署一...
How to read a single character from the user?
...Windows, Linux and OSX: http://code.activestate.com/recipes/134892/
class _Getch:
"""Gets a single character from standard input. Does not echo to the
screen."""
def __init__(self):
try:
self.impl = _GetchWindows()
except ImportError:
self.impl = _Ge...