Question

调用getGenerics()给了我一个通用函数及其相应包的列表：

> getGenerics()
An object of class "ObjectsWithPackage":

Object:  "-"    "!="   "$"    "$<-"  "%%"   "%/%"  "&"    "*"    "/"    "["    "[[<-" "[<-"  "^"    "|"    "+"   
Package: "base" "base" "base" "base" "base" "base" "base" "base" "base" "base" "base" "base" "base" "base" "base"

Object:  "<"    "<="   "=="   ">"    ">="   "abs"  "acos" "acosh" "addNextMethod" "Arith" "asin" "asinh" "atan"
Package: "base" "base" "base" "base" "base" "base" "base" "base"  "methods"       "base"  "base" "base"  "base"

Object:  "atanh" "body<-" "cbind2"  "ceiling" "coerce"  "coerce<-" "Compare" "Complex" "cos"  "cosh" "cospi"
Package: "base"  "base"   "methods" "base"    "methods" "methods"  "methods" "base"    "base" "base" "base" 

Object:  "cummax" "cummin" "cumprod" "cumsum" "digamma" "exp"  "expm1" "floor" "gamma" "initialize" "kronecker"
Package: "base"   "base"   "base"    "base"   "base"    "base" "base"  "base"  "base"  "methods"    "base"     

Object:  "lgamma" "loadMethod" "log"  "log10" "log1p" "log2" "Logic" "Math" "Math2"   "Ops"  "rbind2"  "round"
Package: "base"   "methods"    "base" "base"  "base"  "base" "base"  "base" "methods" "base" "methods" "base" 

Object:  "show"    "sign" "signif" "sin"  "sinh" "sinpi" "slotsFromS3" "sqrt" "Summary" "tan"  "tanh" "tanpi"
Package: "methods" "base" "base"   "base" "base" "base"  "methods"     "base" "base"    "base" "base" "base" 

Object:  "trigamma" "trunc"
Package: "base"     "base"

但是如果指定了包getGenerics('package:base')，则返回null。为什么？如何纠正这个？

> getGenerics('package:base')
An object of class "ObjectsWithPackage":

Object: 
Package:

Answer 1

我们可以使用@提取所需的那些，因为它是一个S4类

getGenerics()[getGenerics()@package =="base"]

指定基本包环境时，getGenerics返回NULL

1 个答案: