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Copy files from one directory into an existing directory
...lly like this syntax, but for some reason it doesn't work with mv. Does anyone know why?
– Martin von Wittich
Sep 16 '13 at 11:18
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How to update a value, given a key in a hashmap?
...ng function, which will be called to compute a new value based on existing one.
For example,
Map<String, Integer> words = new HashMap<>();
words.put("hello", 3);
words.put("world", 4);
words.computeIfPresent("hello", (k, v) -> v + 1);
System.out.println(words.get("hello"));
Altern...
How much does it cost to develop an iPhone application? [closed]
How much can a developer charge for an iPhone app like Twitterrific ?
10 Answers
10
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How can I remove duplicate rows?
...qlinthewild.co.za/index.php/2010/03/23/… Two SELECTs then were produced, one using the LEFT JOIN + WHERE IS NULL technique, the other using the NOT IN one. Then I proceeded with the execution plans, and guess what? The query costs were 18% for LEFT JOIN against 82% for NOT IN, a big surprise to me...
Good Java graph algorithm library? [closed]
Has anyone had good experiences with any Java libraries for Graph algorithms. I've tried JGraph and found it ok, and there are a lot of different ones in google. Are there any that people are actually using successfully in production code or would recommend?
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What is the difference between map and flatMap and a good use case for each?
Can someone explain to me the difference between map and flatMap and what is a good use case for each?
16 Answers
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MPICH vs OpenMPI
Can someone elaborate the differences between the OpenMPI and MPICH implementations of MPI ?
Which of the two is a better implementation ?
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Efficiency of purely functional programming
Does anyone know what is the worst possible asymptotic slowdown that can happen when programming purely functionally as opposed to imperatively (i.e. allowing side-effects)?
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Drop multiple tables in one shot in mysql
How to drop multiple tables from one single database at one command.
something like,
4 Answers
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Why use ICollection and not IEnumerable or List on many-many/one-many relationships?
...exts, that type will yield slightly better performance than would a standalone heap object. Compilers which duck-type enumerators (as both C# and vb.net do) can take advantage of this when generating foreach code. If the List<T> is cast to IEnumrable<T> before the foreach, the IEnumera...