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How to tell if a string is not defined in a Bash shell script
... not set, you can use:
if [ -z "${VAR+xxx}" ]; then echo VAR is not set at all; fi
if [ -z "$VAR" ] && [ "${VAR+xxx}" = "xxx" ]; then echo VAR is set but empty; fi
You probably can combine the two tests on the second line into one with:
if [ -z "$VAR" -a "${VAR+xxx}" = "xxx" ]; then echo VA...
Is using 'var' to declare variables optional? [duplicate]
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@codemeit : javascript is full of pitfalls like this, but all in all it's a beautiful and very pleasant language. Don't hate it. Just know the pitfalls and leave them out of your code.
– Stefano Borini
Mar 21 '10 at 1:25
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How does “this” keyword work within a function?
...a certain value, depending on how you invoke the function. This is often called the invocation pattern.
There are four ways to invoke functions in javascript. You can invoke the function as a method, as a function, as a constructor, and with apply.
As a Method
A method is a function that's atta...
JavaScript REST client Library [closed]
Is there a JavaScript library which allow me to perform all the REST operation like ( GET , POST , PUT and DELETE over HTTP or HTTPS )?
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What's the deal with a leading underscore in PHP class methods?
... { to give it some extra weight.
I've never heard of developers prefacing all their methods with underscores, so I can't begin to explain what causes that.
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Storing C++ template function definitions in a .CPP file
...post the relevant parts in the answer itself? Why is such referencing even allowed on SO. I have no clue what to look for in this link as it has been heavily changed since.
– Ident
Aug 16 '15 at 21:57
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Remove all child elements of a DOM node in JavaScript
How would I go about removing all of the child elements of a DOM node in JavaScript?
32 Answers
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Which is preferred: Nullable.HasValue or Nullable != null?
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The compiler replaces null comparisons with a call to HasValue, so there is no real difference. Just do whichever is more readable/makes more sense to you and your colleagues.
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How do I check that multiple keys are in a dict in a single pass?
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Well, you could do this:
>>> if all (k in foo for k in ("foo","bar")):
... print "They're there!"
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They're there!
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Python: reload component Y imported with 'from X import Y'?
... verse (import this from interactive prompt to see the Zen of Python); and all the reasons why namespaces are a honking great idea (immediate local visual clues that the name's being looked up, ease of mocking/injecting in tests, ability to reload, ability for a module to change flexibly by redefini...