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Data structure: insert, remove, contains, get random element, all at O(1)
... I don't know of any hashtables that let you get an element like that, and if there are any, I can't imagine that this would be a constant time operation. I would be interested to be proven wrong on either count.
– guildner
Apr 16 '11 at 6:10
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SQL join: selecting the last records in a one-to-many relationship
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If you want to include customers who never made a purchase, then change JOIN purchase p1 ON (c.id = p1.customer_id) to LEFT JOIN purchase p1 ON (c.id = p1.customer_id)
– GordonM
Dec 8 '1...
Precise Financial Calculation in JavaScript. What Are the Gotchas?
...now what mistakes to avoid when using JavaScript to do this type of math—if it is possible at all!
7 Answers
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Visual Studio: ContextSwitchDeadlock
... necessarily mean your code has an issue, just that there is a potential. If you go to Debug > Exceptions in the menu and expand the Managed Debugging Assistants, you will find ContextSwitchDeadlock is enabled. If you disable this, VS will no longer warn you when items are taking a long time to...
Efficiently checking if arbitrary object is NaN in Python / numpy / pandas?
...oduced, which is why pandas has the tools to deal with it.
Datetimes too (if you use pd.NaT you won't need to specify the dtype)
In [24]: s = Series([Timestamp('20130101'),np.nan,Timestamp('20130102 9:30')],dtype='M8[ns]')
In [25]: s
Out[25]:
0 2013-01-01 00:00:00
1 NaT
2 2...
How to do case insensitive search in Vim
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Also, \c can appear anywhere in the pattern, so if you type a pattern and then decide you wanted a case-insensitive search, just add a \c at the end.
– Alok Singhal
Feb 18 '10 at 9:20
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Find index of a value in an array
...t;/param>
///<returns>The index of the first matching item, or -1 if no items match.</returns>
public static int FindIndex<T>(this IEnumerable<T> items, Func<T, bool> predicate) {
if (items == null) throw new ArgumentNullException("items");
if (predicate == n...
How to convert a Binary String to a base 10 integer in Java
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You need to specify the radix. There's an overload of Integer#parseInt() which allows you to.
int foo = Integer.parseInt("1001", 2);
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How to programmatically click a button in WPF?
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WPF takes a slightly different approach than WinForms here. Instead of having the automation of a object built into the API, they have a separate class for each object that is responsible for automating it. In this case you need the ButtonAutoma...
Mongo: find items that don't have a certain field
...e using $exists:
db.things.find( { a : { $exists : false } } ); // return if a is missing
When is true, $exists matches the documents that contain the field, including documents where the field value is null. If is false, the query returns only the documents that do not contain the field.
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