I am going to try to keep this dead simple. A “callback” is any function that is called by another function which takes the first function as a parameter. A lot of the time, a “callback” is a function that is called when something happens. That something can be called an “event” in programmer-speak. Imagine … Read more
I think the easiest way is to declare a simple object literal: var myInstance = { method1: function () { // … }, method2: function () { // … } }; If you want private members on your singleton instance, you can do something like this: var myInstance = (function() { var privateVar=””; function privateMethod … Read more
The other answers have done a good job at explaining duck typing and the simple answer by tzot: Python does not have variables, like other languages where variables have a type and a value; it has names pointing to objects, which know their type. However, one interesting thing has changed since 2010 (when the question … Read more
Figured it out for myself in the end. It is simple, I was just missing the ** operator to unpack the dictionary So my example becomes: d = dict(p1=1, p2=2) def f2(p1,p2): print p1, p2 f2(**d)
You want the typeof operator. Specifically: if (typeof variable !== ‘undefined’) { // the variable is defined }
static and class both associate a method with a class, rather than an instance of a class. The difference is that subclasses can override class methods; they cannot override static methods. class properties will theoretically function in the same way (subclasses can override them), but they’re not possible in Swift yet.
With the -c (command) argument (assuming your file is named foo.py): $ python -c ‘import foo; print foo.hello()’ Alternatively, if you don’t care about namespace pollution: $ python -c ‘from foo import *; print hello()’ And the middle ground: $ python -c ‘from foo import hello; print hello()’
Although Bash has a return statement, the only thing you can specify with it is the function’s own exit status (a value between 0 and 255, 0 meaning “success”). So return is not what you want. You might want to convert your return statement to an echo statement – that way your function output could … Read more
From man bash on return [n]; Causes a function to stop executing and return the value specified by n to its caller. If n is omitted, the return status is that of the last command executed in the function body. … on exit [n]: Cause the shell to exit with a status of n. If … Read more
From the Python PEP 8 — Style Guide for Python Code: Descriptive: Naming Styles The following special forms using leading or trailing underscores are recognized (these can generally be combined with any case convention): _single_leading_underscore: weak “internal use” indicator. E.g. from M import * does not import objects whose name starts with an underscore. single_trailing_underscore_: … Read more