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When would you use a WeakHashMap or a WeakReference?
The use of weak references is something that I've never seen an implementation of so I'm trying to figure out what the use case for them is and how the implementation would work. When have you needed to use a WeakHashMap or WeakReference and how was it used?
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Preventing scroll bars from being hidden for MacOS trackpad users in WebKit/Blink
WebKit/Blink's (Safari/Chrome) default behaviour on MacOS since 10.7 (Mac OS X Lion) is to hide scroll bars from trackpad users when they're not in use. This can be confusing ; the scroll bar is often the only visual cue that an element is scrollable.
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How to map calculated properties with JPA and Hibernate
My Java bean has a childCount property. This property is not mapped to a database column . Instead, it should be calculated by the database with a COUNT() function operating on the join of my Java bean and its children. It would be even better if this property could be calculated on demand / "laz...
Where can I learn how to write C code to speed up slow R functions? [closed]
What's the best resource for learning how to write C code for use with R? I know about the system and foreign language interfaces section of R extensions, but I find it pretty hard going. What are good resources (both online and offline) for writing C code for use with R?
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How does a Breadth-First Search work when looking for Shortest Path?
I've done some research, and I seem to be missing one small part of this algorithm. I understand how a Breadth-First Search works, but I don't understand how exactly it will get me to a specific path, as opposed to just telling me where each individual node can go. I guess the easiest way to explain...
How do I get currency exchange rates via an API such as Google Finance? [closed]
Now, I did find the Google Finance API and started looking through that but I found a lot of info about portfolios, transactions, positions & other stuff I know nothing about.
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What does functools.wraps do?
In a comment on this answer to another question , someone said that they weren't sure what functools.wraps was doing. So, I'm asking this question so that there will be a record of it on StackOverflow for future reference: what does functools.wraps do, exactly?
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How do you read from stdin?
I'm trying to do some of the code golf challenges, but they all require the input to be taken from stdin . How do I get that in Python?
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How to override to_json in Rails?
This issue was not properly explored. The real issue lies within render :json .
4 Answers
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jQuery vs document.querySelectorAll
I heard several times that jQuery's strongest asset is the way it queries and manipulates elements in the DOM: you can use CSS queries to create complex queries that would be very hard to do in regular javascript .
However , as far as I know, you can achieve the same result with document.querySele...