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What makes Lisp macros so special?
...(e.g. Infix Notation Math for Clojure).
Here is a more concrete example:Python has list comprehensions built into the language. This gives a simple syntax for a common case. The line
divisibleByTwo = [x for x in range(10) if x % 2 == 0]
yields a list containing all even numbers between 0 and ...
builtins.TypeError: must be str, not bytes
I've converted my scripts from Python 2.7 to 3.2, and I have a bug.
2 Answers
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What's the difference between a Python “property” and “attribute”?
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Properties are a special kind of attribute. Basically, when Python encounters the following code:
spam = SomeObject()
print(spam.eggs)
it looks up eggs in spam, and then examines eggs to see if it has a __get__, __set__, or __delete__ method — if it does, it's a property. If...
Make sure only a single instance of a program is running
Is there a Pythonic way to have only one instance of a program running?
20 Answers
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Python append() vs. + operator on lists, why do these give different results?
...Little history
For fun, a little history: the birth of the array module in Python in February 1993. it might surprise you, but arrays were added way after sequences and lists came into existence.
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Merge PDF files
Is it possible, using Python, to merge separate PDF files?
9 Answers
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Is it Pythonic to use list comprehensions for just side effects?
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It is very anti-Pythonic to do so, and any seasoned Pythonista will give you hell over it. The intermediate list is thrown away after it is created, and it could potentially be very, very large, and therefore expensive to create.
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Difference between __getattr__ vs __getattribute__
...ily.
New-style classes derive from object, old-style classes are those in Python 2.x with no explicit base class. But the distinction between old-style and new-style classes is not the important one when choosing between __getattr__ and __getattribute__.
You almost certainly want __getattr__.
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What's the difference between dist-packages and site-packages?
I'm a bit miffed by the python package installation process. Specifically, what's the difference between packages installed in the dist-packages directory and the site-packages directory?
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JavaScript variable assignments from tuples
In other languages like Python 2 and Python 3, you can define and assign values to a tuple variable, and retrieve their values like this:
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