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What is the scope of variables in JavaScript?
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TLDR
JavaScript has lexical (also called static) scoping and closures. This means you can tell the scope of an identifier by looking at the source code.
The four scopes are:
Global - visible by everything
Function - visible within a function (and its sub-fun...
Check if a variable is a string in JavaScript
...king both typeof and instanceof feels like good advice if your code may be called by others'. @MarkAmery's postmessage edge case matters if you're asking "what was I just postmessaged?" - but you'd expect that to be handled at the interface and not allowed to propagate. Elsewhere, it seems correct ...
How to extend an existing JavaScript array with another array, without creating a new array
... then pushed to the back of the array. So a.push('x', 'y', 'z') is a valid call that will extend a by 3 elements. apply is a method of any function that takes an array and uses its elements as if they were all given explicitly as positional elements to the function. So a.push.apply(a, ['x', 'y', 'z'...
Call int() function on every list element?
... list comprehensions mentioned by adamk. Without the square brackets, it's called a generator expression, and is a very memory-efficient way of passing a list of arguments to a method. A good discussion is available here: Generator Expressions vs. List Comprehension
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Why can't I define a default constructor for a struct in .NET?
...to declare parameterless constructors in structs - but they still won't be called in all situations (e.g. for array creation) (in the end this feature was not added to C# 6).
EDIT: I've edited the answer below due to Grauenwolf's insight into the CLR.
The CLR allows value types to have paramete...
Which is more efficient, a for-each loop, or an iterator?
...r form. Therefore, you should choose the form of loop that is most aesthetically appealing to you, for most people that will be the for-each loop, as that has less boilerplate code.
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Use 'import module' or 'from module import'?
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With that last example, can you still call 'foo.bar = "orange"' to update 'bar' inside 'foo'?
– velocirabbit
May 3 '15 at 21:42
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Where to find extensions installed folder for Google Chrome on Mac?
...ise, look in the <profile user name>/Extensions directory.
If that didn't help, you can always do a custom search.
Go to chrome://extensions/, and find out the ID of an extension (32 lowercase letters) (if not done already, activate "Developer mode" first).
Open the terminal, cd to the ...
(this == null) in C#!
...erGenerated method doesn't make sense; if you look at the IL (below), it's calling the method on a null string (!).
.locals init (
[0] string CS$1$0000)
L_0000: ldloc.0
L_0001: call instance string CompilerBug.Program/Derived::CheckNull()
L_0006: stloc.0
L_0007: br.s L_...
This type of CollectionView does not support changes to its SourceCollection from a thread different
...l); but it is giving syntax error. Look like Send method is expecting some callback method name. I have tried various options like delegate with parameter but it is not allowing to have my custom parameter. I am very new to this kind of syntax, so it would really helpful if you can provide me synt...