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What is the difference between pluck and collect in Rails?
...er.first.gifts.collect(&:id)
You have objects with all fields loaded and you simply get the id thanks to the method based on Enumerable.
So:
if you only need the id with Rails 4, use ids: User.first.gifts.ids
if you only need some fields with Rails 4, use pluck: User.first.gifts.pluck(:id, ...
How to create a custom attribute in C#
I have tried lots of times but still I am not able to understand the usage of custom attributes (I have already gone through lots of links).
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Moving from CVS to Git: $Id$ equivalent?
...through a bunch of questions asking about simple source code control tools and Git seemed like a reasonable choice. I have it up and running, and it works well so far. One aspect that I like about CVS is the automatic incrementation of a version number.
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How to make ruler always be shown in Sublime text 2?
I use Sublime Text 2 and want a Ruler to be shown in every file with specific line-height. But I have to show it manually in every file.
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What are the pros and cons of both Jade and EJS for Node.js templating? [closed]
Jade versus EJS, what are the pros and cons of each and what purposes are each designed for?
2 Answers
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__FILE__ macro shows full path
The standard predefined macro __FILE__ available in C shows the full path to the file. Is there any way to short the path? I mean instead of
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Why would anyone use set instead of unordered_set?
C++0x is introducing unordered_set which is available in boost and many other places. What I understand is that unordered_set is hash table with O(1) lookup complexity. On the other hand, set is nothing but a tree with log(n) lookup complexity. Why on earth would anyone use set instead ...
NoSql vs Relational database
...nal. For those situations, NoSQL can be helpful.
With that said, NoSQL stands for "Not Only SQL". It's not intended to knock SQL or supplant it.
SQL has several very big advantages:
Strong mathematical basis.
Declarative syntax.
A well-known language in Structured Query Language (SQL).
Th...
How to dynamically compose an OR query filter in Django?
...eries there is also the option to use built in Q() object's constants Q.OR and Q.AND together with the add() method like so:
list = [1, 2, 3]
# it gets a bit more complicated if we want to dynamically build
# OR queries with dynamic/unknown db field keys, let's say with a list
# of db fields that c...
How to get maximum value from the Collection (for example ArrayList)?
... list. E.g. suppose the arrayList stored values are : 10, 20, 30, 40, 50 and the max
value would be 50 .
15 Answers
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