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How to check 'undefined' value in jQuery
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JQuery library was developed specifically to simplify and to unify certain JavaScript functionality.
However if you need to check a variable against undefined value, there is no need to invent any special method, since JavaScript has a typeof operator, which is...
Symbolic links and synced folders in Vagrant
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Virtualbox does not allow symlinks on shared folders for security reasons. To enable symlinks the following line needs to be added to the vm provider config block in the Vagrantfile:
config.vm.provider "virtualbox" do |v|
v.customize ["sete...
How to determine a Python variable's type?
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It is so simple. You do it like this.
print(type(variable_name))
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assertEquals vs. assertEqual in python
...as been deprecated as well:
Method Name | Deprecated alias(es)
_________________________________________________________
assertEqual() | failUnlessEqual, assertEquals
From 25.3.7.1.1. Deprecated aliases
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Hidden features of Perl?
What are some really useful but esoteric language features in Perl that you've actually been able to employ to do useful work?
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transform object to array with lodash
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You can do
var arr = _.values(obj);
For documentation see here.
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Find the most common element in a list
...roups by the item only (via operator.itemgetter). The auxiliary function, called once per grouping during the max computation, receives and internally unpacks a group - a tuple with two items (item, iterable) where the iterable's items are also two-item tuples, (item, original index) [[the items of ...
How to set JAVA_HOME in Linux for all users
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For all users, I would recommend placing the following line in /etc/profile
export JAVA_HOME=$(readlink -f /usr/bin/javac | sed "s:/bin/javac::")
This will update dynamically and works well with the alternatives system. Do not...
Python's json module, converts int dictionary keys to strings
...which implement a __hash__ method. (The Lua docs suggest that it automatically uses the object's ID as a hash/key even for mutable objects and relies on string interning to ensure that equivalent strings map to the same objects).
In Perl, Javascript, awk and many other languages the keys for hash...
Is there an equivalent to CTRL+C in IPython Notebook in Firefox to break cells that are running?
...errupt the entire iPython Notebook server. This will stop iPython Notebook alltogether, which means it won't be possible to restart or save your work, so this is obviously not a great solution (you need to hit CTRL+C twice because it's a safety feature so that people don't do it by accident). In cas...