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Ruby: Easiest Way to Filter Hash Keys?
...dated.
I'm adding an update here to help others avoid getting sidetracked by this answer like I did.
As the other answer mentions, Ruby >= 2.5 added the Hash#slice method which was previously only available in Rails.
Example:
> { one: 1, two: 2, three: 3 }.slice(:one, :two)
=> {:one=>...
What characters can be used for up/down triangle (arrow without stem) for display in HTML?
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Unicode arrows heads:
▲ - U+25B2 BLACK UP-POINTING TRIANGLE
▼ - U+25BC BLACK DOWN-POINTING TRIANGLE
▴ - U+25B4 SMALL BLACK UP-POINTING TRIANGLE
▾ - U+25BE SMALL BLACK DOWN-POINTING TRIANGLE
For ▲ and ▼ use ▲ and ▼ respect...
How to list active / open connections in Oracle?
Is there any hidden table, system variable or something to show active connections in a given moment?
9 Answers
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What is the difference between class and instance attributes?
Is there any meaningful distinction between:
5 Answers
5
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Reshape three column data frame to matrix (“long” to “wide” format) [duplicate]
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There are many ways to do this. This answer starts with what is quickly becoming the standard method, but also includes older methods and various other methods from answers to similar questions scattered around this site.
tmp <- data.frame(x=gl(2,3, labels=letters[24:25]),
y...
PHP abstract properties
Is there any way to define abstract class properties in PHP?
9 Answers
9
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Is Java's assertEquals method reliable?
...issues when comparing two Strings . It seems that String.equals() is a better approach. Well, I'm doing JUnit testing and my inclination is to use assertEquals(str1, str2) . Is this a reliable way to assert two Strings contain the same content? I would use assertTrue(str1.equals(str2)) , bu...
The ViewData item that has the key 'MY KEY' is of type 'System.String' but must be of type 'IEnumera
I am trying to populate a dropdown list from a database mapped with Linq-2-SQL, using ASP.NET MVC 2, and keep getting this error.
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Python argparse mutual exclusive group
...options within the group mutually exclusive.
What you're looking for is subcommands. Instead of prog [ -a xxxx | [-b yyy -c zzz]], you'd have:
prog
command 1
-a: ...
command 2
-b: ...
-c: ...
To invoke with the first set of arguments:
prog command_1 -a xxxx
To invoke with th...
CSS Child vs Descendant selectors
I am a bit confused between these 2 selectors.
8 Answers
8
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