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Immutability of Strings in Java
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str is not an object, it's a reference to an object. "Hello" and "Help!" are two distinct String objects. Thus, str points to a string. You can change what it points to, but not that which it points at.
Take this code, for example:
String s1 = "He...
Ignore python multiple return value
... -1: this "convention" sucks when you add gettext functionality to someone else's code (that defines a function called '_') so it should be banned
– nosklo
Jan 11 '09 at 13:32
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How do I check OS with a preprocessor directive?
...need my code to do different things based on the operating system on which it gets compiled. I'm looking for something like this:
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Is there a built-in function to print all the current properties and values of an object?
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Print that dictionary however fancy you like:
>>> print l
['ArithmeticError', 'AssertionError', 'AttributeError',...
or
>>> from pprint import pprint
>>> pprint(l)
['ArithmeticError',
'AssertionError',
'AttributeError',
'BaseException',
'DeprecationWarning',
......
Purpose of Python's __repr__
...for end users.
A simple example:
>>> class Point:
... def __init__(self, x, y):
... self.x, self.y = x, y
... def __repr__(self):
... return 'Point(x=%s, y=%s)' % (self.x, self.y)
>>> p = Point(1, 2)
>>> p
Point(x=1, y=2)
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How to return a value from __init__ in Python?
I have a class with an __init__ function.
10 Answers
10
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Standard alternative to GCC's ##__VA_ARGS__ trick?
There is a well-known problem with empty args for variadic macros in C99.
10 Answers
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Using property() on classmethods
I have a class with two class methods (using the classmethod() function) for getting and setting what is essentially a static variable. I tried to use the property() function with these, but it results in an error. I was able to reproduce the error with the following in the interpreter:
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How to join components of a path when you are constructing a URL in Python
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Since, from the comments the OP posted, it seems he doesn't want to preserve "absolute URLs" in the join (which is one of the key jobs of urlparse.urljoin;-), I'd recommend avoiding that. os.path.join would also be bad, for exactly the same reason.
So, I'd use so...
Python __call__ special method practical example
...method nicely to implement a consistent API for form validation. You can write your own validator for a form in Django as a function.
def custom_validator(value):
#your validation logic
Django has some default built-in validators such as email validators, url validators etc., which broadly fa...