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Getting multiple keys of specified value of a generic Dictionary?
...e, perhaps maintain two dictionary mapping key->value and value->List_of_keys. If you do the latter you will trade storage for look up speed. It wouldn't take much to turn @Cybis example into such a data structure.
s...
How do I check if a string is a number (float)?
...
It's not provided 'out of the box' because if is_number(s): x = float(x) else: // fail is the same number of lines of code as the try: x = float(x) catch TypeError: # fail. This utility function is an entirely unecessary abstraction.
– ovangle
...
What does the 'b' character do in front of a string literal?
...coding instead of with unicode escapes (eg. b'\xff\xfe\xe12' instead of '\u32e1').
– detly
Jun 8 '11 at 2:44
7
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Alphabet range in Python
...
>>> import string
>>> string.ascii_lowercase
'abcdefghijklmnopqrstuvwxyz'
If you really need a list:
>>> list(string.ascii_lowercase)
['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w...
What is “thread local storage” in Python, and why do I need it?
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Shog9
141k3232 gold badges219219 silver badges231231 bronze badges
answered Sep 20 '08 at 0:31
Aaron MaenpaaAar...
Rolling or sliding window iterator?
...f window(seq, n=2):
it = iter(seq)
win = deque((next(it, None) for _ in xrange(n)), maxlen=n)
yield win
append = win.append
for e in it:
append(e)
yield win
In my tests it handily beats everything else posted here most of the time, though pillmuncher's tee versi...
What tools are there for functional programming in C?
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answered Oct 19 '08 at 18:32
ephemientephemient
173k3232 gold badges249249 silver badges372372 bronze badges
...
Is there a performance difference between i++ and ++i in C++?
... this->data += 1;
return *this;
}
Foo Foo::operator++(int ignored_dummy_value) // called for i++
{
Foo tmp(*this); // variable "tmp" cannot be optimized away by the compiler
++(*this);
return tmp;
}
Since the compiler isn't generating code, but just calling an operator++ ...
Split string in Lua?
...%s, like %D is the negation of %d. Additionally, %w is equal to [A-Za-z0-9_] (other characters might be supported depending on your locale).
– Lars Gyrup Brink Nielsen
Jan 2 '14 at 22:00
...
Best way to select random rows PostgreSQL
...ery:
SELECT count(*) AS ct -- optional
, min(id) AS min_id
, max(id) AS max_id
, max(id) - min(id) AS id_span
FROM big;
The only possibly expensive part is the count(*) (for huge tables). Given above specifications, you don't need it. An estimate will do just fine,...