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ActiveRecord, has_many :through, and Polymorphic Associations
... model should allow you do exactly what you're looking for.
class Widget < ActiveRecord::Base
has_many :widget_groupings
has_many :people, :through => :widget_groupings, :source => :grouper, :source_type => 'Person'
has_many :aliens, :through => :widget_groupings, :source =>...
When would you use the Builder Pattern? [closed]
...ern is that once constructors are 4 or 5 parameters long it becomes difficult to remember the required order of the parameters as well as what particular constructor you might want in a given situation.
One alternative you have to the Telescoping Constructor Pattern is the JavaBean Pattern where yo...
jQuery.inArray(), how to use it right?
...nswer comes from the first paragraph of the documentation check if the results is greater than -1, not if it's true or false.
The $.inArray() method is similar to JavaScript's native .indexOf() method in that it returns -1 when it doesn't find a match. If the first element within the array matches ...
How does the String class override the + operator?
...ing method of the referenced object with no arguments; but
if the result of invoking the toString method is null, then the
string "null" is used instead.
The toString method is defined by the primordial class Object
(§4.3.2). Many classes override it, notably Boolean, Character,...
Function for Factorial in Python
...um
return fact
or a recursive approach:
def factorial(n):
if n < 2:
return 1
else:
return n * factorial(n-1)
Note that the factorial function is only defined for positive integers so you should also check that n >= 0 and that isinstance(n, int). If it's not, ra...
DDD - the rule that Entities can't access Repositories directly
... name thats already been used by someone else. I'd like that rule to be built into by ChatUser entity, but its not very easy to do if you can't hit the repository from there. So what should I do?
– codeulike
Apr 22 '11 at 20:06
...
How do you do block comments in YAML?
...
some combination works in eclipse > 4.6 with built in support for YAML
– Faraz
Jun 13 '16 at 16:16
4
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jQuery selector for inputs with square brackets in the name attribute
..., which provides the escape character to the selector... ah, the joys of multiple levels of character escaping.
– Peter
Mar 2 '10 at 17:04
...
What exactly do “u” and “r” string flags do, and what are raw string literals?
... and forward directions, because there's no raw string type, it's just an alternative syntax to express perfectly normal string objects, byte or unicode as they may be.
And yes, in Python 2.*, u'...' is of course always distinct from just '...' -- the former is a unicode string, the latter is a byt...
How to split the name string in mysql?
...);
SET item = SUBSTR(fullstr, inipos, endpos - inipos);
IF item <> '' AND item IS NOT NULL THEN
USE_THE_ITEM_STRING;
END IF;
SET inipos = endpos + 1;
UNTIL inipos >= maxlen END REPEAT;
...