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How do I check in JavaScript if a value exists at a certain array index?
... element with index i is defined to be part of the array if i is between 0 and array.length - 1 inclusive. If i is not in this range it's not in the array.
So by concept, arrays are linear, starting with zero and going to a maximum, without any mechanism for having "gaps" inside that range where n...
windows service vs scheduled task
What are the cons and pros of windows services vs scheduled tasks for running a program repeatedly (e.g. every two minutes)?
...
How to create id with AUTO_INCREMENT on Oracle?
It appears that there is no concept of AUTO_INCREMENT in Oracle, up until and including version 11g.
16 Answers
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Remove an element from a Bash array
...
The following works as you would like in bash and zsh:
$ array=(pluto pippo)
$ delete=pluto
$ echo ${array[@]/$delete}
pippo
$ array=( "${array[@]/$delete}" ) #Quotes when working with strings
If need to delete more than one element:
...
$ delete=(pluto pippo)
for de...
Flatten nested dictionaries, compressing keys
...iterating the dict by key/value, creating new keys for your new dictionary and creating the dictionary at final step.
import collections
def flatten(d, parent_key='', sep='_'):
items = []
for k, v in d.items():
new_key = parent_key + sep + k if parent_key else k
if isinstan...
Jackson and generic type reference
...is a well-known problem with Java type erasure: T is just a type variable, and you must indicate actual class, usually as Class argument. Without such information, best that can be done is to use bounds; and plain T is roughly same as 'T extends Object'. And Jackson will then bind JSON Objects as Ma...
Is there any significant difference between using if/else and switch-case in C#?
... (unlike many other languages) also allows to switch on string constants - and this works a bit differently. It's obviously not practical to build jump tables for strings of arbitrary lengths, so most often such switch will be compiled into stack of IFs.
But if number of conditions is big enough t...
Declaring abstract method in TypeScript
...The name property is marked as protected. This was added in TypeScript 1.3 and is now firmly established.
The makeSound method is marked as abstract, as is the class. You cannot directly instantiate an Animal now, because it is abstract. This is part of TypeScript 1.6, which is now officially live....
How can I rename a database column in a Ruby on Rails migration?
...mething else or do nothing
end
end
For Rails 3.1 use:
While, the up and down methods still apply, Rails 3.1 receives a change method that "knows how to migrate your database and reverse it when the migration is rolled back without the need to write a separate down method".
See "Active Record...
How to save and restore multiple different sessions in Vim?
...like
:mksession ~/mysession.vim
Then later you can source that vim file and you'll have your old session back:
:source ~/mysession.vim
or open vim with the -S option:
$ vim -S ~/mysession.vim
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