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Scala best way of turning a Collection into a Map-by-key?

...Traversable[V].mapBy( V => K) were better! – oxbow_lakes Jul 14 '10 at 21:17 7 Be aware that t...
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C# pattern to prevent an event handler hooked twice [duplicate]

...ution and the best one (considering performance) is: private EventHandler _foo; public event EventHandler Foo { add { _foo -= value; _foo += value; } remove { _foo -= value; } } No Linq using required. No need to check for null before cancelling a subscrip...
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How do I format a string using a dictionary in python-3.x?

... Python 3.2 introduced format_map. Similar to str.format(**mapping), except that mapping is used directly and not copied to a dict. This is useful if for example mapping is a dict subclass – diapir Jan 17 '15 at 14:...
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What is the purpose of double curly braces in React's JSX syntax?

... an object literal inlined in the prop value. It's the same as var obj = {__html: rawMarkup}; <span dangerouslySetInnerHTML={obj} /> share | improve this answer | fo...
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How to get a cross-origin resource sharing (CORS) post request working

...E: response = HttpResponse(json.dumps('{"status" : "success"}')) response.__setitem__("Content-type", "application/json") response.__setitem__("Access-Control-Allow-Origin", "*") return response share | ...
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jasmine: Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL

...out; beforeEach(function() { originalTimeout = jasmine.DEFAULT_TIMEOUT_INTERVAL; jasmine.DEFAULT_TIMEOUT_INTERVAL = 1000000; }); afterEach(function() { jasmine.DEFAULT_TIMEOUT_INTERVAL = originalTimeout; }); it('Template advance', function(doneFn) { ...
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Django in / not in query

... table1.objects.exclude(id__in= table2.objects.filter(your_condition).values_list('id', flat=True)) The exclude function works like the Not operator you where asking for. The attribute flat = True tells to table2 query to return the value_list a...
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How to convert a Django QuerySet to a list

... You could do this: import itertools ids = set(existing_answer.answer.id for existing_answer in existing_question_answers) answers = itertools.ifilter(lambda x: x.id not in ids, answers) Read when QuerySets are evaluated and note that it is not good to load the whole result int...
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Java: Date from unix timestamp

... This is the right way: Date date = new Date (); date.setTime((long)unix_time*1000); share | improve this answer | follow | ...
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What is the difference between sigaction and signal?

...turns. The signal() function (usually) resets the signal action back to SIG_DFL (default) for almost all signals. This means that the signal() handler must reinstall itself as its first action. It also opens up a window of vulnerability between the time when the signal is detected and the handler ...