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Nested defaultdict of defaultdict
...
For an arbitrary number of levels:
def rec_dd():
return defaultdict(rec_dd)
>>> x = rec_dd()
>>> x['a']['b']['c']['d']
defaultdict(<function rec_dd at 0x7f0dcef81500>, {})
>>> print json.dumps(x)
{"a": {"b": {"c": {"d": {}}}}}
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When should you use constexpr capability in C++11?
... "function that always returns 5" is breaking or diluting the meaning of "calling a function". There must be a reason, or a need for this capability or it wouldn't be in C++11. Why is it there?
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Xcode build failure “Undefined symbols for architecture x86_64”
...ometimes the error "build failure “Undefined symbols for architecture x86_64”" may be caused by this. Because, some libs (not Apple's) were compiled for x32 originally and doesn't support x64.
So what you need, is to change the "Architectures" for your project target like this
NB. If you're us...
How do you detect/avoid Memory leaks in your (Unmanaged) code? [closed]
... Valgrind for Linux (and OS X). If you use windose - deleaker - best of all!
– John Smith
Dec 12 '11 at 18:12
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Converting SVG to PNG using C# [closed]
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You can call the command-line version of inkscape to do this:
http://harriyott.com/2008/05/converting-svg-images-to-png-in-c.aspx
Also there is a C# SVG rendering engine, primarily designed to allow SVG files to be used on the web o...
Is there any pythonic way to combine two dicts (adding values for keys that appear in both)?
...t;> A + B
Counter({'c': 7, 'b': 5, 'd': 5, 'a': 1})
Counters are basically a subclass of dict, so you can still do everything else with them you'd normally do with that type, such as iterate over their keys and values.
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In Python how should I test if a variable is None, True or False
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a = 'foo' if a: print 'its true' a is not actually TRUE, it's just not none
– wesm
Apr 3 '15 at 21:06
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How to open a new window on form submit
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No need for Javascript, you just have to add a target="_blank" attribute in your form tag.
<form target="_blank" action="http://example.com"
method="post" id="mc-embedded-subscribe-form"
name="mc-embedded-subscribe-form" class="validate"
>
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What does the “at” (@) symbol do in Python?
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Example
class Pizza(object):
def __init__(self):
self.toppings = []
def __call__(self, topping):
# When using '@instance_of_pizza' before a function definition
# the function gets passed onto 'topping'.
self.toppings.appe...
Do declared properties require a corresponding instance variable?
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In your interface, you can formally declare an instance variable between the braces, or via @property outside the braces, or both. Either way, they become attributes of the class. The difference is that if you declare @property, then you can implement usin...