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Using try vs if in python
... faster if exceptions really are exceptional. If result is None more than 50 % of the time, then using if is probably better.
To support this with a few measurements:
>>> import timeit
>>> timeit.timeit(setup="a=1;b=1", stmt="a/b") # no error checking
0.06379691968322732
>>...
How do I declare an array of weak references in Swift?
...AnyObject> {
mutating func reap () {
self = self.filter { nil != $0.value }
}
}
The use of AnyObject above should be replaced with T - but I don't think the current Swift language allows an extension defined as such.
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How to change to an older version of Node.js
I am running Node.js version v0.5.9-pre on Ubuntu 10.10.
15 Answers
15
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Is there any way to view the currently mapped keys in Vim?
...m, use :index
– Von
Mar 5 '14 at 13:05
31
@Von, you perhaps mean :help index.
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How to create a file in memory for user to download, but not through server?
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20 Answers
20
Active
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PostgreSQL - max number of parameters in “IN” clause?
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According to the source code located here, starting at line 850, PostgreSQL doesn't explicitly limit the number of arguments.
The following is a code comment from line 870:
/*
* We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
* possible if the inputs are all ...
jQuery get textarea text
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answered Sep 28 '08 at 0:17
Eran GalperinEran Galperin
81.9k2222 gold badges112112 silver badges132132 bronze badges
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When should I use malloc in C and when don't I?
... string as read-only. You cannot make changes to it. Example:
some_memory[0] = 'h';
Is asking for trouble.
On the other hand
some_memory = (char *)malloc(size_to_allocate);
is allocating a char array ( a variable) and some_memory points to that allocated memory. Now this array is both read a...
How do you delete all text above a certain line
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508
dgg
will delete everything from your current line to the top of the file.
d is the deletion ...
Python Dictionary Comprehension
... like.
>>> d = {n: n**2 for n in range(5)}
>>> print d
{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
If you want to set them all to True:
>>> d = {n: True for n in range(5)}
>>> print d
{0: True, 1: True, 2: True, 3: True, 4: True}
What you seem to be asking for is a way ...