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Why doesn't Python have a sign function?
...;>> math.copysign(1, -4)
-1.0
>>> math.copysign(1, 3)
1.0
If you get sick of passing two whole arguments, you can implement sign this way, and it will still be compatible with the IEEE stuff mentioned by others:
>>> sign = functools.partial(math.copysign, 1) # either of th...
How do I check if there are duplicates in a flat list?
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Use set() to remove duplicates if all values are hashable:
>>> your_list = ['one', 'two', 'one']
>>> len(your_list) != len(set(your_list))
True
share
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How to find all combinations of coins when given some dollar value
...rful book Generatingfunctionology: math.upenn.edu/~wilf/DownldGF.html) and if you mean an expression like (1+√5)^n, it takes Ω(log n) time to compute, not constant time.
– ShreevatsaR
Jul 10 '09 at 18:33
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Replace values in list using Python [duplicate]
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Build a new list with a list comprehension:
new_items = [x if x % 2 else None for x in items]
You can modify the original list in-place if you want, but it doesn't actually save time:
items = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
for index, item in enumerate(items):
if not (item ...
Why are these numbers not equal?
...equal function. Or rather, since all.equal gives lots of detail about the differences if there are any, isTRUE(all.equal(...)).
if(isTRUE(all.equal(i,0.15))) cat("i equals 0.15") else cat("i does not equal 0.15")
yields
i equals 0.15
Some more examples of using all.equal instead of == (the las...
What is this operator in MySQL?
...erefore supported on other databases, unlike <=>, which is MySQL-specific.
You can think of them as specialisations of MySQL's <=>:
'a' IS NULL ==> 'a' <=> NULL
'a' IS NOT NULL ==> NOT('a' <=> NULL)
Based on this, your particular query (fragment) can be converted t...
What is the difference between & and && in Java?
I always thought that && operator in Java is used for verifying whether both its boolean operands are true , and the & operator is used to do Bit-wise operations on two integer types.
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Does Python have a ternary conditional operator?
If Python does not have a ternary conditional operator, is it possible to simulate one using other language constructs?
26 ...
How to test if list element exists?
I would like to test if an element of a list exists, here is an example
7 Answers
7
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How to tell if a tag failed to load
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The "onload" listener will be fired even if there's a javascript error.
– Luca Matteis
Feb 11 '09 at 21:38
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