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Bookmark or Share- Initialization of an ArrayList in one line - Stack Overflowclass A {} class B extends A {} public List getAList() { return Arrays.asList(new B()); } The above results in a compiler error, because List (which is what is returned by Arrays.asList) is not a subclass of List, even though you can add Objects of type B to a List object. To get around this, you need to do something like:
- What is the difference between Python's list methods append and extend?my_list + another_list creates a third list in memory, so you can return the result of it, but it requires that the second iterable be a list. my_list += another_list modifies the list in-place (it is the in-place operator, and lists are mutable objects, as we've seen) so it does not create a new list. It also works like extend, in that the ...
- python - How to find list intersection? - Stack Overflowfrom nose.tools import assert_equal ''' Given two lists, print out the list of overlapping elements ''' def overlap(l_a, l_b): ''' compare the two lists l_a and l_b and return the overlapping elements (intersecting) between the two ''' #edge case is when they are the same lists if l_a == l_b: return [] #no overlapping elements output = [] if ...
- slice - How slicing in Python works - Stack OverflowIf your choice of a, b, and c allows overlap with the range above as you traverse using rules for a,b,c above you will either get a list with elements (touched during traversal) or you will get an empty list. One last thing: if a and b are equal, then also you get an empty list:
- python - How to deep copy a list? - Stack OverflowIn Python, there is a module called copy with two useful functions:. import copy copy.copy() copy.deepcopy() copy() is a shallow copy function.
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