Tutorial by Examples: arg

You can define a function that takes an arbitrary number of keyword (named) arguments by using the double star ** before a parameter name: def print_kwargs(**kwargs): print(kwargs) When calling the method, Python will construct a dictionary of all keyword arguments and make it available in ...

A common use case for *args in a function definition is to delegate processing to either a wrapped or inherited function. A typical example might be in a class's __init__ method class A(object): def __init__(self, b, c): self.y = b self.z = c class B(A): def __init__(...

You can use a dictionary to assign values to the function's parameters; using parameters name as keys in the dictionary and the value of these arguments bound to each key: def test_func(arg1, arg2, arg3): # Usual function with three arguments print("arg1: %s" % arg1) print("a...

Some functions only work on a certain type of argument: function foo(tab) return tab.bar end --> returns nil if tab has no field bar, which is acceptable --> returns 'attempt to index a number value' if tab is, for example, 3 --> which is unacceptable function kungfoo(tab) ...

When you create an argparse ArgumentParser() and run your program with '-h' you get an automated usage message explaining what arguments you can run your software with. By default, positional arguments and conditional arguments are separated into two categories, for example, here is a small script ...

The effect of using the * operator on an argument when calling a function is that of unpacking the list or a tuple argument def print_args(arg1, arg2): print(str(arg1) + str(arg2)) a = [1,2] b = tuple([3,4]) print_args(*a) # 12 print_args(*b) # 34 Note that the length of the starr...

Racket functions can also have keyword arguments, which are specified with a keyword followed by the argument expression. A keyword begins with the characters #:, so a keyword argument looks like #:keyword arg-expr. Within a function call this looks like (function #:keyword arg-expr). > (define ...

Even though Python natively supports big integers, taking the nth root of very large numbers can fail in Python. x = 2 ** 100 cube = x ** 3 root = cube ** (1.0 / 3) OverflowError: long int too large to convert to float When dealing with such large integers, you will need to use a custom f...

Python 3 allows you to define function arguments which can only be assigned by keyword, even without default values. This is done by using star * to consume additional positional parameters without setting the keyword parameters. All arguments after the * are keyword-only (i.e. non-positional) arg...

When given an argument, the when-statement matches the argument against the branches in sequence. The matching is done using the == operator which performs null checks and compares the operands using the equals function. The first matching one will be executed. when (x) { "English" -...

C++11 In C++11, compilers are required to implicitly move from a local variable that is being returned. Moreover, most compilers can perform copy elision in many cases and elide the move altogether. As a result of this, returning large objects that can be moved cheaply no longer requires special ha...

You can pass parameters to I18n t method: # Example config/locales/en.yml en: page: users: "%{users_count} users currently online" # In models, controller, etc... I18n.t('page.users', users_count: 12) # In views # ERB <%= t('page.users', users_count: 12) %> #S...

This is MATLAB's long-winded way of saying that it cannot find the function that you're trying to call. There are a number of reasons you could get this error: That function was introduced after your current version of MATLAB The MATLAB online documentation provides a very nice feature which allow...

Often times, responsive web design involves media queries, which are CSS blocks that are only executed if a condition is satisfied. This is useful for responsive web design because you can use media queries to specify different CSS styles for the mobile version of your website versus the desktop ver...

The intent attribute of a dummy argument in a subroutine or function declares its intended use. The syntax is either one of intent(IN) intent(OUT) intent(INOUT) For example, consider this function: real function f(x) real, intent(IN) :: x f = x*x end function The intent(IN) specif...

When you create a function in TypeScript you can specify the data type of the function's arguments and the data type for the return value Example: function sum(x: number, y: number): number { return x + y; } Here the syntax x: number, y: number means that the function can accept two argum...

Example: function hello(name: string): string { return `Hello ${name}!`; } Here the syntax name: string means that the function can accept one name argument and this argument can only be string and (...): string { means that the return value can only be a string Usage: hello('StackOverfl...

<!-- <moduleDir>/etc/<area>/di.xml --> <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd"> <!-- ... --> <type name="Vendor\Namespace\Model\So...

Once the number of abilities definitions start to grow in number, it becomes more and more difficult to handle the Ability file. The first strategy to handle these issue is to move abilities into meaningful methods, as per this example: class Ability include CanCan::Ability def initialize(...

Functions are objects in Julia. Like any other objects, they can be passed as arguments to other functions. Functions that accept functions are known as higher-order functions. For instance, we can implement an equivalent of the standard library's foreach function by taking a function f as the firs...