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Good examples of Not a Functor/Functor/Applicative/Monad?
...onoid;
instance Monoid Data.Void where
mempty = undefined
mappend _ _ = undefined
mconcat _ = undefined
Since _|_ is a legal value in Haskell, and in fact the only legal value of Data.Void, this meets the Monoid rules. I am unsure what unsafeCoerce has to do with it, because your pro...
What does new self(); mean in PHP?
...etInstance method is in a class name MyClass, the following line :
self::$_instance = new self();
Will do the same as :
self::$_instance = new MyClass();
Edit : a couple more informations, after the comments.
If you have two classes that extend each other, you have two situations :
get...
Types in MySQL: BigInt(20) vs Int(20)
...264 (22003): Out of range value for column 'id' at row 1
mysql> SET sql_mode = '';
Query OK, 0 rows affected, 1 warning (0,00 sec)
mysql> INSERT INTO `test` (`id`) VALUES (401421228216);
Query OK, 1 row affected, 1 warning (0,06 sec)
mysql> SELECT * FROM `test`;
+------------+
| id ...
Why does Javascript's regex.exec() not always return the same value? [duplicate]
... matches by performing the assignment as the loop condition.
var re = /foo_(\d+)/g,
str = "text foo_123 more text foo_456 foo_789 end text",
match,
results = [];
while (match = re.exec(str))
results.push(+match[1]);
DEMO: http://jsfiddle.net/pPW8Y/
If you don't like the placem...
Temporarily disable auto_now / auto_now_add
...s:
# my model
class FooBar(models.Model):
title = models.CharField(max_length=255)
updated_at = models.DateTimeField(auto_now=True, auto_now_add=True)
# my tests
foo = FooBar.objects.get(pk=1)
# force a timestamp
lastweek = datetime.datetime.now() - datetime.timedelta(days=7)
FooBar.obj...
Checking for empty queryset in Django
...is the code I refer to is only an example that it contains a line if not my_objects: to demonstrate that this is how they do it in the docs. All else is utterly irrelevant so I do not get your point. They could as well make a thousand queries and it would still be totally irrelevant as this is not t...
Preferred way to create a Scala list
...
That is, you can now work on that IndexedSeq:
scala> list.foldLeft(0)(_+_)
res0: Int = 55
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How do I use the includes method in lodash to check if an object is in the collection?
...e there is only one instance of {"b": 2}:
var a = {"a": 1}, b = {"b": 2};
_.includes([a, b], b);
> true
On the other hand, the where(deprecated in v4) and find methods compare objects by their properties, so they don't require reference equality. As an alternative to includes, you might want t...
Creating a new dictionary in Python
...
Call dict with no parameters
new_dict = dict()
or simply write
new_dict = {}
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How to update PATH variable permanently from Windows command line?
...mmatically add or modify system environment variables, add them to the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the string "Environment". This allows applications, such as the shell, to ...