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Patricio Moracho
Asked: 2020-08-22 06:59:08 +0800 CST 2020-08-22 06:59:08 +0800 CST

Can an operator be passed as a parameter to a function?

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I would like to build a function like the following:

function(x, y, operador)

The idea is that it receives an operator, for example: +, -, *. /and can return the result of applying the same between xey

r

1 Answers

  1. Best Answer

    Something fantastic about R is that operators are functions like any other, a little more particular that is. They are known as binary functions since they are limited to only two parameters or they are also called infix operators since they allow infix notation .

    To be able to write an operation with an infix notation, you have to use "backticks", example:

    2 + 3 == `+`(2,3)
2 - 3 == `-`(2,3)
2 / 2 == `/`(2,2)
2 * 2 == `*`(2,2)

    So the function could end up looking like this:

    aplicar <- function(x, y, operador) {
  operador(x,y)
}

    and the execution of it could be:

    aplicar(2, 3, `+`)
aplicar(2, 3, `-`)
aplicar(2, 2, `/`)
aplicar(2, 2, `*`)

    It is important to note that there are many more infix operators that we can use using this technique:

    arithmetic

    +   Suma
–   Resta
*   Multiplicación
/   División
^   Exponente
%%  Módulo
%/% División entera

    Comparatives

    <   Menor a 
>   Mayor a
<=  Menor igual a
>=  Mayor igual a
==  Igual
!=  Distinto

    logical

    &   Y lógico
&&  Y lógico (no vectorizado)
|   O lógico
||  O lógico (no vectorizado)

    Note : the negation !or notis a special case as it only expects one parameter:

    `!`(TRUE)
FALSE

    Assignment

    <-, <<-, =  Asignación izquierda
->, ->>     Asignación derecha

    Note: Although the assignment is an infix operator like the others, it collides with certain particularities that have to do with how the parameters of a function are evaluated, which results in it aplicar()not working the way it does with the rest of the operators. .

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