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How to extract the n-th elements from a list of tuples?
I'm trying to obtain the n-th elements from a list of tuples.
7 Answers
7
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How to port data-only volumes from one host to another?
...estore, or migrate data volumes":
BACKUP:
sudo docker run --rm --volumes-from DATA -v $(pwd):/backup busybox tar cvf /backup/backup.tar /data
--rm: remove the container when it exits
--volumes-from DATA: attach to the volumes shared by the DATA container
-v $(pwd):/backup: bind mount the curren...
Efficient way to remove keys with empty strings from a dict
... +1. It's important to note that this does not actually remove the keys from an existing dictionary. Rather, it creates a new dictionary. Usually this is exactly what someone wants and is probably what the OP needs, but it is not what the OP asked for.
– Steven Rumbalski
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Get protocol + host name from URL
In my Django app, I need to get the host name from the referrer in request.META.get('HTTP_REFERER') along with its protocol so that from URLs like:
...
Scala 2.8 breakOut
...efinition of map:
def map[B, That](f : (A) => B)(implicit bf : CanBuildFrom[Repr, B, That]) : That
Note that it has two parameters. The first is your function and the second is an implicit. If you do not provide that implicit, Scala will choose the most specific one available.
About breakOu...
Deleting array elements in JavaScript - delete vs splice
... is not in fact set to the value undefined, rather the property is removed from the array, making it appear undefined. The Chrome dev tools make this distinction clear by printing empty when logging the array.
> myArray[0]
undefined
> myArray
[empty, "b", "c", "d"]
myArray.splice(start,...
Should I inherit from std::exception?
...ecommend that application-specific exception classes in C++ should inherit from std::exception . I'm not clear on the benefits of this approach.
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What's the difference between Sender, From and Return-Path?
What's the difference between an email Sender, From and Return-Path value?
3 Answers
3...
Using 'return' in a Ruby block
...turn 6 * 7
irb(main):008:1> }
LocalJumpError: unexpected return
from (irb):7:in `block in irb_binding'
from (irb):2:in `call'
from (irb):2:in `thing'
from (irb):6
from /home/mirko/.rvm/rubies/ruby-1.9.1-p378/bin/irb:15:in `<main>'
irb(main):009:0> ...
Remove last item from array
...orrectly, @PrithvirajMitra wants two things: 1) To remove the last element from the original array, and 2) return that element as a single element array - ie: [0,1,2] -> [2], leaving behind [0,1]. If that's the case, then [arr.pop()] will do the trick.
– Ben Hull
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