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Explicitly select items from a list or tuple
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list( myBigList[i] for i in [87, 342, 217, 998, 500] )
I compared the answers with python 2.5.2:
19.7 usec: [ myBigList[i] for i in [87, 342, 217, 998, 500] ]
20.6 usec: map(myBigList.__getitem__, (87, 342, 217, 998, 500))
22.7 usec: itemgetter(87, 342...
Can I use a collection initializer for Dictionary entries?
... new Dictionary<int, string> {
{ 1, "Adam" },
{ 2, "Bart" },
{ 3, "Charlie" }
};
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How are multi-dimensional arrays formatted in memory?
...eter, bad things are going to happen. Here's a quick example:
int array1[3][2] = {{0, 1}, {2, 3}, {4, 5}};
In memory looks like this:
0 1 2 3 4 5
exactly the same as:
int array2[6] = { 0, 1, 2, 3, 4, 5 };
But if you try to pass array1 to this function:
void function1(int **a);
you'll ge...
Python try…except comma vs 'as' in except
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The definitive document is PEP-3110: Catching Exceptions
Summary:
In Python 3.x, using as is required to assign an exception to a variable.
In Python 2.6+, use the as syntax, since it is far less ambiguous and forward compatible with Python 3.x.
In Pyth...
Install a module using pip for specific python version
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NoobEditor
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answered Jun 6 '12 at 18:13
Charles DuffyCha...
How to dynamically compose an OR query filter in Django?
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13 Answers
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How would I get a cron job to run every 30 minutes?
I'm looking to add a crontab entry to execute a script every 30 minutes, on the hour and 30 minutes past the hour or something close. I have the following, but it doesn't seem to run on 0.
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Asynchronous shell commands
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answered Mar 3 '10 at 1:06
Carl NorumCarl Norum
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Cost of len() function
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360
It's O(1) (constant time, not depending of actual length of the element - very fast) on every ...
Python list iterator behavior and next(iterator)
...e(10)))
>>> for i in a:
... print(i)
... next(a)
...
0
1
2
3
4
5
6
7
8
9
So 0 is the output of print(i), 1 the return value from next(), echoed by the interactive interpreter, etc. There are just 5 iterations, each iteration resulting in 2 lines being written to the terminal.
If y...