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javascript set a variable if undefined
... x === 'undefined') ? your_default_value : x;
On newer browsers it's actually safe to write:
var x = (x === undefined) ? your_default_value : x;
but be aware that it is possible to subvert this on older browsers where it was permitted to declare a variable named undefined that has a defined val...
How to properly check if std::function is empty in C++11?
...'re not checking for an empty lambda, but whether the std::function has a callable target stored in it. The check is well-defined and works because of std::function::operator bool which allows for implicit conversion to bool in contexts where boolean values are required (such as the conditional expr...
Pandas index column title or name
...rty
In [7]: df.index.name
Out[7]: 'Index Title'
In [8]: df.index.name = 'foo'
In [9]: df.index.name
Out[9]: 'foo'
In [10]: df
Out[10]:
Column 1
foo
Apples 1
Oranges 2
Puppies 3
Ducks 4
...
How do I create an array of strings in C?
...ar *a[2];
a[0] = "blah";
a[1] = "hmm";
When you do it like this you will allocate an array of two pointers to const char. These pointers will then be set to the addresses of the static strings "blah" and "hmm".
If you do want to be able to change the actual string content, the you have to do some...
Why are exclamation marks used in Ruby methods?
...eone else might have a reference to. Here's a simple example for strings:
foo = "A STRING" # a string called foo
foo.downcase! # modifies foo itself
puts foo # prints modified foo
This will output:
a string
In the standard libraries, there are a lot of places you'll see pairs of ...
(Deep) copying an array using jQuery [duplicate]
...y an (ordered, not associative) array of objects. I'm using jQuery. I initially tried
8 Answers
...
How can I split a JavaScript string by white space or comma?
... @Bergi: Well, it's both more strict than what I suggest (only one comma allowed, in front) and more loose (split on all whitespace) than what the OP asked for. IMHO it would be simply worse -- consider the input spaces , before commas.
– Jon
Apr 27 '12 at 7:...
Private module methods in Ruby
...itten) to do this is by creating a class within the module that deals with all the logic, and the module just provides a convenient method, e.g.
module GTranslate
class Translator
def perform( text ); translate( text ); end
private
def translate( text )
# do some private stuff...
Why does flowing off the end of a non-void function without returning a value not produce a compiler
...C++ 6.6.3/2 is not the same in C.
gcc will give you a warning if you call it with -Wreturn-type option.
-Wreturn-type Warn whenever a function is defined with a return-type that
defaults to int. Also warn about any
return statement with no return-value
in a function whose return-type ...
Using the field of an object as a generic Dictionary key
...s true), that they have the same hash-code. For example, you might "return FooID;" as the GetHashCode() if you want that as the match. You can also implement IEquatable<Foo>, but that is optional:
class Foo : IEquatable<Foo> {
public string Name { get; set;}
public int FooID {ge...