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What's the meaning of “=>” (an arrow formed from equals & greater than) in JavaScript?
...other words, you can often use them in place of expressions like function (foo) {...}. But they have some important differences. For example, they do not bind their own values of this (see below for discussion).
Arrow functions are part of the ECMAscript 6 specification. They are not yet supported i...
How do I parse XML in Python?
...like:
for type_tag in root.findall('bar/type'):
value = type_tag.get('foobar')
print(value)
And similar, usually pretty simple, code patterns.
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Accessing a class's constants
...
What you posted should work perfectly:
class Foo
CONSTANT_NAME = ["a", "b", "c"]
end
Foo::CONSTANT_NAME
# => ["a", "b", "c"]
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What is the difference between a symbolic link and a hard link?
...that might help, using any Linux(ish) console.
Create two files:
$ touch foo; touch bar
Enter some Data into them:
$ echo "Cat" > foo
$ echo "Dog" > bar
(Actually, I could have used echo in the first place, as it creates the files if they don't exist... but never mind that.)
And as exp...
Which is more preferable to use: lambda functions or nested functions ('def')?
...= lambda: 0
>>> type(l)
<class 'function'>
>>> def foo(): return 0
...
>>> type(foo)
<class 'function'>
>>> type(foo) is type(l)
True
Since lambdas are functions, they're first-class objects.
Both lambdas and functions:
can be passed around as an...
How do you query for “is not null” in Mongo?
...ist when there is something in the field). Here is a sample data set:
db.foo.find()
{ "_id" : ObjectId("544540b31b5cf91c4893eb94"), "imageUrl" : "http://example.com/foo.jpg" }
{ "_id" : ObjectId("544540ba1b5cf91c4893eb95"), "imageUrl" : "http://example.com/bar.jpg" }
{ "_id" : ObjectId("544540c51b...
Swift Programming: getter/setter in stored property
...rarily wrong, you should wrap a computed property around it.
private var _foo:Int = 0
var foo:Int {
get {
return _foo
}
set {
if(newValue > 999) {
_foo = 999
} else {
_foo = newValue
}
}
}
Or:
private var _foo:Int = 0
var...
Macro vs Function in C
...
#define print(x, y) printf(x y) /* accidentally forgot comma */
print("foo %s", "bar") /* prints "foo %sbar" */
Inline functions and constants help to avoid many of these problems with macros, but aren't always applicable. Where macros are deliberately used to specify polymorphic behavior, uni...
How to return a value from __init__ in Python?
...you want to return an instance variable (or function).
>>> class Foo:
... def __init__(self):
... return 42
...
>>> foo = Foo()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: __init__() should return None
...
node.js shell command execution
...f the data has been read off of stdout. As such, when you run
console.log(foo.stdout);
you get whatever happens to be stored in foo.stdout at the moment, and there's no guarantee what that will be because your child process might still be running.
Second is that stdout is a readable stream, so 1...