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Find the extension of a filename in Ruby
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That's really basic stuff:
irb(main):002:0> accepted_formats = [".txt", ".pdf"]
=> [".txt", ".pdf"]
irb(main):003:0> File.extname("example.pdf") # get the extension
=> ".pdf"
irb(main):004:0> accepted_formats.include? File.extname("example.pdf")
=&g...
What are “first class” objects?
...cos = makeDerivative( Math.sin, 0.000001);
// cos(0) ~> 1
// cos(pi/2) ~> 0
Source.
Entities that are not first class objects are referred to as second-class objects. Functions in C++ are second class because they can't be dynamically created.
Regarding the edit:
EDIT. When one ...
Where is Vagrant saving changes to the VM?
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2 Answers
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MongoDB: update every document on one field
...ocument. In the Mongo shell, or with any MongoDB client:
$version >= 3.2:
db.foo.updateMany( {}, <update> )
{} is the condition (the empty condition matches any document)
3.2 > $version >= 2.2:
db.foo.update( {}, <update>, { multi: true } )
{} is the condition (the em...
Two statements next to curly brace in an equation
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edited Feb 27 '15 at 13:05
Tombart
24.4k1212 gold badges104104 silver badges116116 bronze badges
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Which access modifiers are implied when not specified?
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2 Answers
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How do I automatically update a timestamp in PostgreSQL
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203
To populate the column during insert, use a DEFAULT value:
CREATE TABLE users (
id serial n...
What's the difference of $host and $http_host in Nginx
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$host is a variable of the Core module.
$host
This variable is equal to line Host in the he...
How do I convert a org.w3c.dom.Document object to a String?
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edited Mar 26 '14 at 6:03
Ashish Aggarwal
2,92722 gold badges2020 silver badges4343 bronze badges
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How to implement a queue with three stacks?
...a.edu/webs/people/okasaki/jfp95.ps and it seems that he actually uses only 2 stacks for the O(1) version that has lazy evaluation. The problem is that it's really based on lazy evaluation. The question is if it can be translated to a 3-stack algorithm without lazy evaluation.
UPDATE: Another relate...