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What is `params.require(:person).permit(:name, :age)` doing in Rails 4?
...od throws an error. It returns an instance of ActionController::Parameters for the key passed into require.
The permit method returns a copy of the parameters object, returning only the permitted keys and values. When creating a new ActiveRecord model, only the permitted attributes are passed into ...
Bash: Copy named files recursively, preserving folder structure
...s out "cp --parents" isn't possible on mac, but it's nice to know the flag for other unixen. rsync -R is the simplest portable solution for this problem.
– mahemoff
Nov 1 '09 at 1:42
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How can you check which options vim was compiled with?
I'd like to know which compilation options were used for my Vim binary. Is there any way to query this?
3 Answers
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Extract subset of key-value pairs from Python dictionary object?
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You could try:
dict((k, bigdict[k]) for k in ('l', 'm', 'n'))
... or in Python 3 Python versions 2.7 or later (thanks to Fábio Diniz for pointing that out that it works in 2.7 too):
{k: bigdict[k] for k in ('l', 'm', 'n')}
Update: As Håvard S points out,...
Access denied for user 'root'@'localhost' while attempting to grant privileges. How do I grant privi
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Notice how the output of
SHOW GRANTS FOR 'root'@'localhost';
did not say 'ALL PRIVILEGES' but had to spell out what root@localhost has.
GRANT ALL PRIVILEGES will fail, because a user can not grant what he/she does not have,
and the server seem to think someth...
How do I convert datetime to ISO 8601 in PHP
How do I convert my time from 2010-12-30 23:21:46 to ISO 8601 date format? (-_-;)
6 Answers
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I want to copy table contained from one database and insert onto another database table
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Great solution if the table has no foreign key constraints. I used this for making a copy of an entire database instead of just one table. For that I'd recommend using mysqldump command.
– thorne51
Jun 18 '14 at 9:33
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Is std::unique_ptr required to know the full definition of T?
...of their members can be instantiated with incomplete types. The motivation for this is to support idioms such as pimpl using smart pointers, and without risking undefined behavior.
Undefined behavior can occur when you have an incomplete type and you call delete on it:
class A;
A* a = ...;
delete ...
How to Unit test with different settings in Django?
Is there any simple mechanism for overriding Django settings for a unit test? I have a manager on one of my models that returns a specific number of the latest objects. The number of objects it returns is defined by a NUM_LATEST setting.
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Is there a builtin identity function in python?
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@Marcin Thanks for the remark. I have added advantages/drawbacks of the two in order not to mislead anyone. And now, I really believe there should have been a builtin function that accepts any number of parameters and is a true identity :)
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