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Why do we need fibers
... each. Think about it: normally all the Enumerable methods, including map, select, include?, inject, and so on, all work on the elements yielded by each. But what if an object has other iterators other than each?
irb(main):001:0> "Hello".chars.select { |c| c =~ /[A-Z]/ }
=> ["H"]
irb(main):00...
How to add “on delete cascade” constraints?
...hy until you see "Constraints"), or you can query the information schema.
select *
from information_schema.key_column_usage
where position_in_unique_constraint is not null
share
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improve this ans...
How do I set the default font size in Vim?
...n supports it)
set guifont=*
This will pop up a menu that allows you to select the font. After selecting the font, type
set guifont?
To show what the current guifont is set to. After that copy that line into your vimrc or gvimrc. If there are spaces in the font add a \ to escape the space.
se...
Django ManyToMany filter()
...d it.
the above code will end up generating SQL that looks something like:
SELECT * FROM users WHERE id IN (SELECT user_id FROM userzones WHERE zone_id IN (1,2,3))
which is nice because it doesn't have any intermediate joins that could cause duplicate users to be returned
...
.prop('checked',false) or .removeAttr('checked')?
...to jQuery 3.0, using .removeAttr() on a boolean attribute such as checked, selected, or readonly would also set the corresponding named property to false. This behavior was required for ancient versions of Internet Explorer but is not correct for modern browsers because the attribute represents the ...
Parse JSON in C#
...result = new List<DynamicJsonObject>((result as ArrayList).ToArray().Select(x => new DynamicJsonObject(x as IDictionary<string, object>)));
}
else if (result is ArrayList)
{
result = new List<object>((result as ArrayList).ToArray());
}...
How can I merge two hashes without overwritten duplicate keys in Ruby?
... and defaults without overwriting the destination hash, you may check with select if the key is already present in the destination hash. Here's the pure Ruby solution without Rails:
options = { "a" => 100, "b" => 200 }
defaults = { "b" => 254, "c" => 300 }
options.merge!(defaults.selec...
What is the equivalent of bigint in C#?
...
I just had a script that returned the primary key of an insert and used a
SELECT @@identity
on my bigint primary key, and I get a cast error using long - that was why I started this search. The correct answer, at least in my case, is that the type returned by that select is NUMERIC which equates t...
How to check if a particular service is running on Ubuntu
...
For Ubuntu (checked with 12.04)
You can get list of all services and select by color one of them with 'grep':
sudo service --status-all | grep postgres
Or you may use another way if you know correct name of service:
sudo service postgresql status
...
How can I generate a diff for a single file between two branches in github
...GITHUB WEB Page for previous checkin.
Go to that file in the github, then select HISTORY. This will open page with list of checkin comments link like below.
On clicking on it will show the code changes. After clicking the history; you can click on packages to see package level all files checkins...