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How do I override __getattr__ in Python without breaking the default behavior?
...ttributes in the instance that match the name. For instance, if you access foo.bar, then __getattr__ will only be called if foo has no attribute called bar. If the attribute is one you don't want to handle, raise AttributeError:
class Foo(object):
def __getattr__(self, name):
if some_pr...
How to check if an object is a generator object in python?
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@JAB, @Piotr: Reflected to address all the possibilities of what the OP can mean , thanks JAB :)
– mouad
Jun 20 '11 at 19:57
1
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Immutable vs Mutable types
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Almost, but not exactly. Technically, all variables are passed by reference in Python, but have a semantics more like pass by value in C. A counterexample to your analogy is if you do def f(my_list): my_list = [1, 2, 3]. With pass-by-reference in C, the val...
Escape a string for a sed replace pattern
...capes themselves, forward slash for end of statement and & for replace all):
ESCAPED_REPLACE=$(printf '%s\n' "$REPLACE" | sed -e 's/[\/&]/\\&/g')
# Now you can use ESCAPED_REPLACE in the original sed statement
sed "s/KEYWORD/$ESCAPED_REPLACE/g"
If you ever need to escape the KEYWORD s...
See changes to a specific file using git
...s, but, as far as I understood, it is directory based. This means it gives all the changes of all files on the current directory.
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Forward declaration of a typedef in C++
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+1 in the end because while you technically can't "forward-typedef" (i.e. you can't write "typedef A;"), you can almost certainly accomplish what the OP wants to accomplish using your trick above.
– j_random_hacker
Apr 30 '09...
Match multiple cases classes in scala
...String parameters, and want to treat B and C the same, so:
def matcher(l: Foo): String = {
l match {
case A() => "A"
case B(_) | C(_) => "B"
case _ => "default"
}
}
If you must, must, must extract the parameter and treat them in the same code block, you could:
def matche...
Empty set literal?
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Actually, set literals have been backported to Python 2.7, so they are not only available strictly in Python 3.
– Jim Brissom
May 25 '11 at 20:56
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Static class initializer in PHP
I have an helper class with some static functions. All the functions in the class require a ‘heavy’ initialization function to run once (as if it were a constructor).
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How do I create a variable number of variables?
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'eggs'
For cases where you're thinking of doing something like
var1 = 'foo'
var2 = 'bar'
var3 = 'baz'
...
a list may be more appropriate than a dict. A list represents an ordered sequence of objects, with integer indices:
lst = ['foo', 'bar', 'baz']
print(lst[1]) # prints bar, becau...