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How to get a complete list of object's methods and attributes?
...nts accepted by the getattr built-in function. As the user can reimplement __getattr__, suddenly allowing any kind of attribute, there is no possible generic way to generate that list. The dir function returns the keys in the __dict__ attribute, i.e. all the attributes accessible if the __getattr__ ...
How do I override __getattr__ in Python without breaking the default behavior?
I want to override the __getattr__ method on a class to do something fancy but I don't want to break the default behavior.
...
C++及Windows异常处理(try，catch; __try,__finally, __except) - C/C++ - ...
C++及Windows异常处理(try，catch; __try,__finally, __except)C++及Windows异常处理(try，catch; __try,__finally; __try, __except)一道笔试题引起的探究题目：
int* p = 0x00000000; // pointer to NULL
puts( "hello ");
__try{
puts( "in try ...
Why does Python use 'magic methods'?
...s', e.g. to make its length available, an object implements a method, def __len__(self) , and then it is called when you write len(obj) .
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Are static class variables possible in Python?
...es are one honking great idea -- let's do more of those!
>>> Test.__dict__
{'i': 6, ...}
>>> t.__dict__
{'i': 5}
>>> u.__dict__
{}
Notice how the instance variable t.i got out of sync with the "static" class variable when the attribute i was set directly on t. This is be...
Is there a TRY CATCH command in Bash
...ojects:
trycatch.sh
#!/bin/bash
function try()
{
[[ $- = *e* ]]; SAVED_OPT_E=$?
set +e
}
function throw()
{
exit $1
}
function catch()
{
export ex_code=$?
(( $SAVED_OPT_E )) && set +e
return $ex_code
}
function throwErrors()
{
set -e
}
function ignoreErrors()...
Proper way to declare custom exceptions in modern Python?
... (or pass extra args), do this:
class ValidationError(Exception):
def __init__(self, message, errors):
# Call the base class constructor with the parameters it needs
super(ValidationError, self).__init__(message)
# Now for your custom code...
self.errors = erro...
C++ mark as deprecated
...his all I got was a Microsoft specific solution; #pragma deprecated and __declspec(deprecated) .
7 Answers
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Dictionary vs Object - which is more efficient and why?
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Have you tried using __slots__?
From the documentation:
By default, instances of both old and new-style classes have a dictionary for attribute storage. This wastes space for objects having very few instance variables. The space consumption can ...
Python memoising/deferred lookup property decorator
...
from boltons.cacheutils import cachedproperty
class Foo(object):
def __init__(self):
self.value = 4
@cachedproperty
def cached_prop(self):
self.value += 1
return self.value
f = Foo()
print(f.value) # initial value
print(f.cached_prop) # cached property is c...