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Test whether a list contains a specific value in Clojure
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Ah, contains?... supposedly one of the top five FAQs re: Clojure.
It does not check whether a collection contains a value; it checks whether an item could be retrieved with get or, in other words, whether a collection contains a key. This makes sense for sets (which can be thought of as mak...
Using Phonegap for Native Application development [closed]
I recently came across Phonegap . Have anyone of you tried it. Its an incredible tool which claims that developers can use HTML 5 based framework like Sencha touch and Jquery at the same time
having access to native features on phone. Also the code is portable from Android to Iphone with some effo...
What is the basic difference between the Factory and Abstract Factory Design Patterns? [closed]
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With the Factory pattern, you produce instances of implementations (Apple, Banana, Cherry, etc.) of a particular interface -- say, IFruit.
With the Abstract Factory pattern, you provide a way for anyone to provide their own f...
How to design a database for User Defined Fields?
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If performance is the primary concern, I would go with #6... a table per UDF (really, this is a variant of #2). This answer is specifically tailored to this situation and the description of the data distribution and access patterns described.
Pros:
Because you indicate tha...
How to create module-wide variables in Python? [duplicate]
...e a way to set up a global variable inside of a module? When I tried to do it the most obvious way as appears below, the Python interpreter said the variable __DBNAME__ did not exist.
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How to duplicate object properties in another object?
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edited Oct 11 '19 at 21:49
Zoltán Matók
3,68122 gold badges2626 silver badges5151 bronze badges
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how to check if object already exists in a list
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It depends on the needs of the specific situation. For example, the dictionary approach would be quite good assuming:
The list is relatively stable (not a lot of inserts/deletions, which dictionaries are not optimized for)
T...
How do I profile memory usage in Python?
I've recently become interested in algorithms and have begun exploring them by writing a naive implementation and then optimizing it in various ways.
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Is there a NumPy function to return the first index of something in an array?
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Yes, here is the answer given a NumPy array, array, and a value, item, to search for:
itemindex = numpy.where(array==item)
The result is a tuple with first all the row indices, then all the column indices.
For example, if an array is two dimensions and it contained your item at two loc...
Why is 1/1/1970 the “epoch time”?
...ns of unix measured system time in 1/60 s intervals. This meant that a 32-bit unsigned integer could only represent a span of time less than 829 days. For this reason, the time represented by the number 0 (called the epoch) had to be set in the very recent past. As this was in the early 1970s, the e...