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Getting the difference between two sets
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Set#removeAll
Removes from this set all of its elements that are contained in the specified collection (optional operation). If the specified collection is also a set, this operation effectively modifies this set so that its value is the asymmetric set difference of the two sets.
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Functional style of Java 8's Optional.ifPresent and if-not-Present?
In Java 8, I want to do something to an Optional object if it is present, and do another thing if it is not present.
12 A...
Python creating a dictionary of lists
...;> d = defaultdict(list)
>>> a = ['1', '2']
>>> for i in a:
... for j in range(int(i), int(i) + 2):
... d[j].append(i)
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>>> d
defaultdict(<type 'list'>, {1: ['1'], 2: ['1', '2'], 3: ['2']})
>>> d.items()
[(1, ['1']), (2, ['1', '2']), (3, ['2'])]
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Replace a string in shell script using a variable
I am using the below code for replacing a string
inside a shell script.
10 Answers
10
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Calling a Fragment method from a parent Activity
I see in the Android Fragments Dev Guide that an "activity can call methods in a fragment by acquiring a reference to the Fragment from FragmentManager, using findFragmentById() or findFragmentByTag() ."
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Export and Import all MySQL databases at one time
... 100 MySQL databases. I want to export all of them at the same time and again import all of them into my MySQL server at one time. How can I do that?
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How to ignore SSL certificate errors in Apache HttpClient 4.0
How do I bypass invalid SSL certificate errors with Apache HttpClient 4.0?
23 Answers
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What is the difference between a HashMap and a TreeMap? [duplicate]
I started learning Java. When would I use a HashMap over a TreeMap?
8 Answers
8
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How to tell Jackson to ignore a field during serialization if its value is null?
How can Jackson be configured to ignore a field value during serialization if that field's value is null.
19 Answers
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Reference list item by index within Django template?
This may be simple, but I looked around and couldn't find an answer. What's the best way to reference a single item in a list from a Django template?
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