英文:
stacking multiple calls of library(…, include.only=…) doesn’t work
问题
自R 3.6版本开始，可以在加载包时使用library(…, include.only=…)选择要加载的函数。
但有时我需要临时加载其他函数，而堆叠多个library(…, include.only=…)不起作用：
> library(stringr, include.only = 'str_length')
> str_length('a')
[1] 1
> library(stringr, include.only = 'str_sub')
> str_sub('a')
Error in str_sub('a') : 找不到函数“str_sub”
> str_length('a')
[1] 1
到目前为止，解决方法是卸载包，然后重新加载：
> devtools::unload('stringr')
> library(stringr, include.only = c('str_length', 'str_sub'))
是否有其他方法可以在不重新加载包的情况下按需加载函数？
英文:
As of R 3.6 it’s possible to choose functions when loading a package with library(…, include.only=…).
But sometimes I’d need other functions on the fly, and stacking multiples library(…, include.only=…) doesn’t work:
> library(stringr, include.only = 'str_length')
> str_length('a')
[1] 1
> library(stringr, include.only = 'str_sub')
> str_sub('a')
Error in str_sub("a") : could not find function "str_sub"
> str_length('a')
[1] 1
so far the workaround is to unload package then reload
> devtools::unload('stringr')
> library(stringr, include.only = c('str_length', 'str_sub'))
is there another way to load functions on demand without reloading package?
答案1
得分: 2
一种选择是将各个函数分配到全局环境中：
str_length <- stringr::str_length
str_length('a')
# 1
str_sub <- stringr::str_sub
str_sub('a')
# "a"
str_length('a')
# 1
或者您可以使用 box：
box::use(stringr[str_length])
str_length('a')
# 1
box::use(stringr[str_sub])
str_sub('a')
# "a"
str_length('a')
# 1
英文:
One option would be to assign individual functions into the global environment:
str_length <- stringr::str_length
str_length('a')
# 1
str_sub <- stringr::str_sub
str_sub('a')
# "a"
str_length('a')
# 1
Or you could use box:
box::use(stringr[str_length])
str_length('a')
# 1
box::use(stringr[str_sub])
str_sub('a')
# "a"
str_length('a')
# 1
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