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Determine the type of an object?
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On instances of object you also have the:
__class__
attribute. Here is a sample taken from Python 3.3 console
>>> str = "str"
>>> str.__class__
<class 'str'>
>>> i = 2
>>> i.__class__
<class 'int'>
>>> class...
enum - getting value of enum on string conversion
...;>> member.name
'red'
>>> member.value
1
You could add a __str__ method to your enum, if all you wanted was to provide a custom string representation:
class D(Enum):
def __str__(self):
return str(self.value)
x = 1
y = 2
Demo:
>>> from enum import E...
Multiprocessing vs Threading Python [duplicate]
...n3
import multiprocessing
import threading
import time
import sys
def cpu_func(result, niters):
'''
A useless CPU bound function.
'''
for i in range(niters):
result = (result * result * i + 2 * result * i * i + 3) % 10000000
return result
class CpuThread(threading.Thre...
How can I add new keys to a dictionary?
...gnoring the keys
Create a dictionary from two lists
data = dict(zip(list_with_keys, list_with_values))
New to Python 3.5
Creating a merged dictionary without modifying originals:
This uses a new featrue called dictionary unpacking.
data = {**data1, **data2, **data3}
New to Python 3.9...
Why does @foo.setter in Python not work for me?
...operty
def x(self):
print 'called getter'
return self._x
@x.setter
def x(self, value):
print 'called setter'
self._x = value
It works:
>>> k = testDec()
>>> k.x
called getter
Traceback (most recent call last):
File "<stdin>"...
How to check if the string is empty?
... the fact that empty sequences are false.
So you should use:
if not some_string:
or:
if some_string:
Just to clarify, sequences are evaluated to False or True in a Boolean context if they are empty or not. They are not equal to False or True.
...
编译器内部的秘密--微软的编译器是如何解析Try/Catch/Throw的 - C/C++ - 清...
...这并不是应该由编译器该干的活。这行语句会变成对函数_CxxThrowException (函数来自MSVCR100.dll或其他类似版本的dll)的调用。 这个函数有编译器内部构建。你喜欢的话，你可以自己调用它。这个函数的第一个参数是指向抛出的异常...
Batch File; List files in directory, only filenames?
...answered May 3 '18 at 10:14
Mike_GreMike_Gre
8111 silver badge33 bronze badges
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From an array of objects, extract value of a property as array
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Check out Lodash's _.pluck() function or Underscore's _.pluck() function. Both do exactly what you want in a single function call!
var result = _.pluck(objArray, 'foo');
Update: _.pluck() has been removed as of Lodash v4.0.0, in favour of _...
How to perform OR condition in django queryset?
...
from django.db.models import Q
User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True))
via Documentation
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