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Is there a simple, elegant way to define singletons? [duplicate]
...se the Instance method. Here's an example:
@Singleton
class Foo:
def __init__(self):
print 'Foo created'
f = Foo() # Error, this isn't how you get the instance of a singleton
f = Foo.instance() # Good. Being explicit is in line with the Python Zen
g = Foo.instance() # Returns already ...
How does JavaScript .prototype work?
...reation), and
The standardized accessor (ie. getter/setter) property named __proto__ (similar to 4.)
Object.getPrototypeOf and Object.setPrototypeOf are preferred over __proto__, in part because the behavior of o.__proto__ is unusual when an object has a prototype of null.
An object's [[Prototype...
Java “lambda expressions not supported at this language level”
...: android { compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 targetCompatibility JavaVersion.VERSION_1_8 } }
– BaDo
Sep 25 '15 at 2:30
...
Proper way to use **kwargs in Python
...icular default value, why not use named arguments in the first place?
def __init__(self, val2="default value", **kwargs):
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What __init__ and self do on Python?
...
In this code:
class A(object):
def __init__(self):
self.x = 'Hello'
def method_a(self, foo):
print self.x + ' ' + foo
... the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidd...
How to get the concrete class name as a string? [duplicate]
...
instance.__class__.__name__
example:
>>> class A():
pass
>>> a = A()
>>> a.__class__.__name__
'A'
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What is the best way to call a script from another script?
...e usual way to do this is something like the following.
test1.py
def some_func():
print 'in test 1, unproductive'
if __name__ == '__main__':
# test1.py executed as script
# do something
some_func()
service.py
import test1
def service_func():
print 'service func'
if __name...
Does python have an equivalent to Java Class.forName()?
...honic way of doing it.
Here's a function that does what you want:
def get_class( kls ):
parts = kls.split('.')
module = ".".join(parts[:-1])
m = __import__( module )
for comp in parts[1:]:
m = getattr(m, comp)
return m
You can use the return value of this ...
How to deal with SettingWithCopyWarning in Pandas?
...H5390 and GH5597 for background discussion.]
df[df['A'] > 2]['B'] = new_val # new_val not set in df
The warning offers a suggestion to rewrite as follows:
df.loc[df['A'] > 2, 'B'] = new_val
However, this doesn't fit your usage, which is equivalent to:
df = df[df['A'] > 2]
df['B'] = ...
Dynamic instantiation from string name of a class in dynamically imported module?
...
You can use getattr
getattr(module, class_name)
to access the class. More complete code:
module = __import__(module_name)
class_ = getattr(module, class_name)
instance = class_()
As mentioned below, we may use importlib
import importlib
module = importlib.imp...