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How to implement __iter__(self) for a container object (Python)
...owing will create an iterator that yields five, and then every item in some_list.
def __iter__(self):
yield 5
yield from some_list
Pre-3.3, yield from didn't exist, so you would have to do:
def __iter__(self):
yield 5
for x in some_list:
yield x
...
How to initialize all members of an array to the same value?
...e same value, without multiple copy-paste, you can use macros:
#define VAL_1X 42
#define VAL_2X VAL_1X, VAL_1X
#define VAL_4X VAL_2X, VAL_2X
#define VAL_8X VAL_4X, VAL_4X
#define VAL_16X VAL_8X, VAL_8X
#define VAL_32X VAL_16X, VAL_16X
#define VAL_64X VAL_32X, VAL_32X
i...
Why exactly is eval evil?
...estion is not specific to LISP. Here is an answer on the same question for PHP, and it applies to LISP, Ruby, and other other language that has an eval:
The main problems with eval() are:
Potential unsafe input. Passing an untrusted parameter is a way to
fail. It is often not a trivial...
Difference between except: and except Exception as e: in Python
...
['__cause__', '__class__', '__context__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__ne__...
Get name of current script in Python
...
You can use __file__ to get the name of the current file. When used in the main module, this is the name of the script that was originally invoked.
If you want to omit the directory part (which might be present), you can use os.path.bas...
Class with Object as a parameter
...
class Classic: pass
class NewStyle(object): pass
print(dir(Classic))
# ['__doc__', '__module__']
print(dir(NewStyle))
# ['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__',...
Pandas selecting by label sometimes return Series, sometimes returns DataFrame
...using? On the latest version, I get a KeyError when I try .loc[[nonexistent_label]].
– Dan Allan
Nov 6 '14 at 16:58
2
...
Object of custom type as dictionary key
...
You need to add 2 methods, note __hash__ and __eq__:
class MyThing:
def __init__(self,name,location,length):
self.name = name
self.location = location
self.length = length
def __hash__(self):
return hash((self.name...
Difference between len() and .__len__()?
Is there any difference between calling len([1,2,3]) or [1,2,3].__len__() ?
4 Answers
...
Inherit docstrings in Python class inheritance
...out this a while ago, and a recipe was created. Check it out here.
"""
doc_inherit decorator
Usage:
class Foo(object):
def foo(self):
"Frobber"
pass
class Bar(Foo):
@doc_inherit
def foo(self):
pass
Now, Bar.foo.__doc__ == Bar().foo.__doc__ == Foo.foo.__doc__...