Mrthdrb

How much RAM could one put in a typical 80386 setup?

Minkowski space

Have astronauts in space suits ever taken selfies? If so, how?

The Two and the One

Do VLANs within a subnet need to have their own subnet for router on a stick?

TGV timetables / schedules?

Today is the Center

The use of multiple foreign keys on same column in SQL Server

How to write a macro that is braces sensitive?

Is it legal for company to use my work email to pretend I still work there?

How does strength of boric acid solution increase in presence of salicylic acid?

Can I make popcorn with any corn?

How to format long polynomial?

Risk of getting Chronic Wasting Disease (CWD) in the United States?

Python: next in for loop

What does "Puller Prush Person" mean?

What would happen to a modern skyscraper if it rains micro blackholes?

Can an x86 CPU running in real mode be considered to be basically an 8086 CPU?

What defenses are there against being summoned by the Gate spell?

Example of a continuous function that don't have a continuous extension

Service Entrance Breakers Rain Shield

Is it possible to do 50 km distance without any previous training?

Why doesn't H₄O²⁺ exist?

What is the word for reserving something for yourself before others do?

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

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty height:90px;width:728px;box-sizing:border-box;

10

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

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
  Apr 3 at 19:45
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you want your function to do? Your first function (calc.simp) still works even after changing the class of z.
  
  – Luis
  Apr 3 at 19:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @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
  Apr 3 at 19:58
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  question is about dispatching? didn't see this keyword anywhere on this page, hence adding it here.
  
  – chinsoon12
  Apr 4 at 0:24
  

  
  
  
  

add a comment | 

10

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

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
  Apr 3 at 19:45
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What do you want your function to do? Your first function (calc.simp) still works even after changing the class of z.
  
  – Luis
  Apr 3 at 19:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @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
  Apr 3 at 19:58
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  question is about dispatching? didn't see this keyword anywhere on this page, hence adding it here.
  
  – chinsoon12
  Apr 4 at 0:24
  

  
  
  
  

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

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 Apr 3 at 19:36

Branda NewbeeBranda Newbee

534

1 Answer
1

active

oldest

votes

9

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 Apr 3 at 20:04

answered Apr 3 at 19:59

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

9

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 Apr 3 at 20:04

answered Apr 3 at 19:59

Josh O'BrienJosh O'Brien

130k18280390

add a comment | 

9

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 Apr 3 at 20:04

answered Apr 3 at 19:59

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 Apr 3 at 20:04

answered Apr 3 at 19:59

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 Apr 3 at 20:04

answered Apr 3 at 19:59

Josh O'BrienJosh O'Brien

130k18280390

answered Apr 3 at 19:59

Josh O'BrienJosh O'Brien

130k18280390

answered Apr 3 at 19:59

Josh O'BrienJosh O'Brien

130k18280390