Yhyjyk

Mathematica command that allows it to read my intentions

What is the idiomatic way to say "clothing fits"?

Is it acceptable for a professor to tell male students to not think that they are smarter than female students?

What's the in-universe reasoning behind sorcerers needing material components?

Size of subfigure fitting its content (tikzpicture)

Short story with a alien planet, government officials must wear exploding medallions

What about the virus in 12 Monkeys?

How to write generic function with two inputs?

Is there an expression that means doing something right before you will need it rather than doing it in case you might need it?

What type of content (depth/breadth) is expected for a short presentation for Asst Professor interview in the UK?

Unlock My Phone! February 2018

How dangerous is XSS?

How do I handle a potential work/personal life conflict as the manager of one of my friends?

Do UK voters know if their MP will be the Speaker of the House?

How to prevent "they're falling in love" trope

What is the most common color to indicate the input-field is disabled?

What killed these X2 caps?

ssTTsSTtRrriinInnnnNNNIiinngg

Plagiarism or not?

Is it possible to create a QR code using text?

How seriously should I take size and weight limits of hand luggage?

Why doesn't using multiple commands with a || or && conditional work?

Can compressed videos be decoded back to their uncompresed original format?

How do I gain back my faith in my PhD degree?

How to write generic function with two inputs?

How to sort a dataframe by multiple column(s)How to join (merge) data frames (inner, outer, left, right)Grouping functions (tapply, by, aggregate) and the *apply familyHow to make a great R reproducible exampleArguments and classes for writing (generic) functions in RWriting generic function for tables that works when the input happens to be vectorHow to retrieve formals of a primitive function?Error within function using solve() in RSubsetting data as generic function in RWriting if / ifelse function in R

9

1

I am a newbee in programming, and I run into an issue with R about generic function: how to write it when there are multiple inputs?

For an easy example, for dataset and function

z <- c(2,3,4,5,8)
calc.simp <- function(a,x)a*x+8
# Test the function:
calc.simp(x=z,a=3)
[1] 14 17 20 23 32

Now I change the class of z:
class(z) <- 'simp'
How should I write the generic function 'calc' as there are two inputs?
My attempts and errors are below:

calc <- function(x) UseMethod('calc',x)
calc(x=z)
Error in calc.simp(x = z) : argument "a" is missing, with no default

And

calc <- function(x,y) UseMethod('calc',x,y)
Error in UseMethod("calc", x, y) : unused argument (y)

My confusion might be a fundamental one as I am just a beginner. Please help! Thank you very much!

r generic-programming

share|improve this question

asked 5 hours ago

Branda NewbeeBranda Newbee

483

New contributor

Branda Newbee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  What do you expect to be returned from calc(x=z)? You aren't giving your function a value for a and your function depends on it. Also you can let your generic function know there may be other argumets with calc <- function(x, ...) UseMethod('calc',x)
  
  – MrFlick
  4 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you want your function to do? Your first function (calc.simp) still works even after changing the class of z.
  
  – Luis
  4 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @MrFlick I simply want to test whether my generic function can work! It helps me understand the dispatch mechanism better. The 'function(x,...)' works perfectly for my question. Thank you so much! :)
  
  – Branda Newbee
  4 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  question is about dispatching? didn't see this keyword anywhere on this page, hence adding it here.
  
  – chinsoon12
  18 mins ago
  

  
  
  
  

add a comment | 

9

1

I am a newbee in programming, and I run into an issue with R about generic function: how to write it when there are multiple inputs?

For an easy example, for dataset and function

z <- c(2,3,4,5,8)
calc.simp <- function(a,x)a*x+8
# Test the function:
calc.simp(x=z,a=3)
[1] 14 17 20 23 32

Now I change the class of z:
class(z) <- 'simp'
How should I write the generic function 'calc' as there are two inputs?
My attempts and errors are below:

calc <- function(x) UseMethod('calc',x)
calc(x=z)
Error in calc.simp(x = z) : argument "a" is missing, with no default

And

calc <- function(x,y) UseMethod('calc',x,y)
Error in UseMethod("calc", x, y) : unused argument (y)

My confusion might be a fundamental one as I am just a beginner. Please help! Thank you very much!

r generic-programming

share|improve this question

asked 5 hours ago

Branda NewbeeBranda Newbee

483

New contributor

Branda Newbee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  What do you expect to be returned from calc(x=z)? You aren't giving your function a value for a and your function depends on it. Also you can let your generic function know there may be other argumets with calc <- function(x, ...) UseMethod('calc',x)
  
  – MrFlick
  4 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you want your function to do? Your first function (calc.simp) still works even after changing the class of z.
  
  – Luis
  4 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @MrFlick I simply want to test whether my generic function can work! It helps me understand the dispatch mechanism better. The 'function(x,...)' works perfectly for my question. Thank you so much! :)
  
  – Branda Newbee
  4 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  question is about dispatching? didn't see this keyword anywhere on this page, hence adding it here.
  
  – chinsoon12
  18 mins ago
  

  
  
  
  

add a comment | 

I am a newbee in programming, and I run into an issue with R about generic function: how to write it when there are multiple inputs?

For an easy example, for dataset and function

z <- c(2,3,4,5,8)
calc.simp <- function(a,x)a*x+8
# Test the function:
calc.simp(x=z,a=3)
[1] 14 17 20 23 32

Now I change the class of z:
class(z) <- 'simp'
How should I write the generic function 'calc' as there are two inputs?
My attempts and errors are below:

calc <- function(x) UseMethod('calc',x)
calc(x=z)
Error in calc.simp(x = z) : argument "a" is missing, with no default

And

calc <- function(x,y) UseMethod('calc',x,y)
Error in UseMethod("calc", x, y) : unused argument (y)

My confusion might be a fundamental one as I am just a beginner. Please help! Thank you very much!

r generic-programming

share|improve this question

asked 5 hours ago

Branda NewbeeBranda Newbee

483

New contributor

Branda Newbee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

z <- c(2,3,4,5,8)
calc.simp <- function(a,x)a*x+8
# Test the function:
calc.simp(x=z,a=3)
[1] 14 17 20 23 32

calc <- function(x) UseMethod('calc',x)
calc(x=z)
Error in calc.simp(x = z) : argument "a" is missing, with no default

calc <- function(x,y) UseMethod('calc',x,y)
Error in UseMethod("calc", x, y) : unused argument (y)

share|improve this question

asked 5 hours ago

Branda NewbeeBranda Newbee

483

New contributor

Branda Newbee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share|improve this question

asked 5 hours ago

Branda NewbeeBranda Newbee

483

New contributor

Branda Newbee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 5 hours ago

Branda NewbeeBranda Newbee

483

New contributor

Branda Newbee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 5 hours ago

Branda NewbeeBranda Newbee

483

1 Answer
1

active

oldest

votes

8

I'd suggest you model your generic function off of the template used by innumerable base R functions as, e.g., mean:

> mean
function (x, ...) 
UseMethod("mean")

In your case, that would translate to the following generic which (if I understand your question correctly) works just fine:

calc <- function(x, ...) UseMethod('calc')

calc.simp <- function(a, x) 
 x <- unclass(x)
 a * x + 8



## Try it out

z <- c(2,3,4,5,8)
class(z) <- "simp"

calc.simp(x = z, 10)
## [1] 28 38 48 58 88

calc(x = z, 10)
## [1] 28 38 48 58 88

share|improve this answer

edited 4 hours ago

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function ()
StackExchange.using("externalEditor", function ()
StackExchange.using("snippets", function ()
StackExchange.snippets.init();
);
);
, "code-snippets");

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "1"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

Branda Newbee is a new contributor. Be nice, and check out our Code of Conduct.

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f55503025%2fhow-to-write-generic-function-with-two-inputs%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

8

I'd suggest you model your generic function off of the template used by innumerable base R functions as, e.g., mean:

> mean
function (x, ...) 
UseMethod("mean")

In your case, that would translate to the following generic which (if I understand your question correctly) works just fine:

calc <- function(x, ...) UseMethod('calc')

calc.simp <- function(a, x) 
 x <- unclass(x)
 a * x + 8



## Try it out

z <- c(2,3,4,5,8)
class(z) <- "simp"

calc.simp(x = z, 10)
## [1] 28 38 48 58 88

calc(x = z, 10)
## [1] 28 38 48 58 88

share|improve this answer

edited 4 hours ago

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390

add a comment | 

8

I'd suggest you model your generic function off of the template used by innumerable base R functions as, e.g., mean:

> mean
function (x, ...) 
UseMethod("mean")

In your case, that would translate to the following generic which (if I understand your question correctly) works just fine:

calc <- function(x, ...) UseMethod('calc')

calc.simp <- function(a, x) 
 x <- unclass(x)
 a * x + 8



## Try it out

z <- c(2,3,4,5,8)
class(z) <- "simp"

calc.simp(x = z, 10)
## [1] 28 38 48 58 88

calc(x = z, 10)
## [1] 28 38 48 58 88

share|improve this answer

edited 4 hours ago

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390

add a comment | 

I'd suggest you model your generic function off of the template used by innumerable base R functions as, e.g., mean:

> mean
function (x, ...) 
UseMethod("mean")

In your case, that would translate to the following generic which (if I understand your question correctly) works just fine:

calc <- function(x, ...) UseMethod('calc')

calc.simp <- function(a, x) 
 x <- unclass(x)
 a * x + 8



## Try it out

z <- c(2,3,4,5,8)
class(z) <- "simp"

calc.simp(x = z, 10)
## [1] 28 38 48 58 88

calc(x = z, 10)
## [1] 28 38 48 58 88

share|improve this answer

edited 4 hours ago

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390

> mean
function (x, ...) 
UseMethod("mean")

calc <- function(x, ...) UseMethod('calc')

calc.simp <- function(a, x) 
 x <- unclass(x)
 a * x + 8



## Try it out

z <- c(2,3,4,5,8)
class(z) <- "simp"

calc.simp(x = z, 10)
## [1] 28 38 48 58 88

calc(x = z, 10)
## [1] 28 38 48 58 88

share|improve this answer

edited 4 hours ago

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390

answered 4 hours ago

Josh O'BrienJosh O'Brien

130k18280390