Hjdcti

How dangerous is XSS?

Should I cover my bicycle overnight while bikepacking?

Ambiguity in the definition of entropy

How do conventional missiles fly?

Avoiding the "not like other girls" trope?

Extract rows of a table, that include less than x NULLs

Is it inappropriate for a student to attend their mentor's dissertation defense?

Why was the shrinking from 8″ made only to 5.25″ and not smaller (4″ or less)?

Method Does Not Exist error message

Apex Framework / library for consuming REST services

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

How much of data wrangling is a data scientist's job?

How would I stat a creature to be immune to everything but the Magic Missile spell? (just for fun)

If human space travel is limited by the G force vulnerability, is there a way to counter G forces?

iPad being using in wall mount battery swollen

Assassin's bullet with mercury

Bullying boss launched a smear campaign and made me unemployable

Plagiarism or not?

What method can I use to design a dungeon difficult enough that the PCs can't make it through without killing them?

Valid term from quadratic sequence?

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

Determining Impedance With An Antenna Analyzer

Are there any examples of a variable being normally distributed that is *not* due to the Central Limit Theorem?

Why would the Red Woman birth a shadow if she worshipped the Lord of the Light?

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
  5 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
  5 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
  29 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
  5 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
  5 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
  29 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