R语言胶水作为一个对象

thtygnil 于 12个月前发布在其他

关注(0)|答案(2)|浏览(126)

我想使用glue函数的输出作为R对象，但它只能作为字符。
例如：如果我尝试-

as.factor((
  str_glue("iris$`{colnames(iris[5])}`")
))

字符串
结果是这样的：

[1] iris$`Species`
Levels: iris$`Species`

型
但我想要这个

as.factor(iris$`Species`)

[1] setosa     setosa     setosa     setosa     setosa     setosa     setosa     setosa     setosa    
 ...
[145] virginica  virginica  virginica  virginica  virginica  virginica 
Levels: setosa versicolor virginica

型

r

来源：https://stackoverflow.com/questions/77442161/glue-as-an-object

2条答案

按热度按时间

vsmadaxz1#

可以用rlang::eval_parse来实现：

rlang:::eval_parse(stringr::str_glue("iris$`{colnames(iris[5])}`"))
#>   [1] setosa     setosa     setosa     setosa     setosa     setosa    
#>   [7] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [13] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [19] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [25] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [31] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [37] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [43] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [49] setosa     setosa     versicolor versicolor versicolor versicolor
#>  [55] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [61] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [67] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [73] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [79] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [85] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [91] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [97] versicolor versicolor versicolor versicolor virginica  virginica 
#> [103] virginica  virginica  virginica  virginica  virginica  virginica 
#> [109] virginica  virginica  virginica  virginica  virginica  virginica 
#> [115] virginica  virginica  virginica  virginica  virginica  virginica 
#> [121] virginica  virginica  virginica  virginica  virginica  virginica 
#> [127] virginica  virginica  virginica  virginica  virginica  virginica 
#> [133] virginica  virginica  virginica  virginica  virginica  virginica 
#> [139] virginica  virginica  virginica  virginica  virginica  virginica 
#> [145] virginica  virginica  virginica  virginica  virginica  virginica 
#> Levels: setosa versicolor virginica

字符串
创建于2023-11-07附带reprex v2.0.2
或者简单地用[[取第五列，这与用`$```取第五列名称相同：

rlang:::eval_parse("iris[[5]]")
#>   [1] setosa     setosa     setosa     setosa     setosa     setosa    
#>   [7] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [13] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [19] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [25] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [31] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [37] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [43] setosa     setosa     setosa     setosa     setosa     setosa    
#>  [49] setosa     setosa     versicolor versicolor versicolor versicolor
#>  [55] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [61] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [67] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [73] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [79] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [85] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [91] versicolor versicolor versicolor versicolor versicolor versicolor
#>  [97] versicolor versicolor versicolor versicolor virginica  virginica 
#> [103] virginica  virginica  virginica  virginica  virginica  virginica 
#> [109] virginica  virginica  virginica  virginica  virginica  virginica 
#> [115] virginica  virginica  virginica  virginica  virginica  virginica 
#> [121] virginica  virginica  virginica  virginica  virginica  virginica 
#> [127] virginica  virginica  virginica  virginica  virginica  virginica 
#> [133] virginica  virginica  virginica  virginica  virginica  virginica 
#> [139] virginica  virginica  virginica  virginica  virginica  virginica 
#> [145] virginica  virginica  virginica  virginica  virginica  virginica 
#> Levels: setosa versicolor virginica

型
创建于2023-11-07附带reprex v2.0.2

赞(0）回复(0）举报 12个月前

u1ehiz5o2#

使用eval和parse或parse_expr：

my_str <- str_glue("iris$`{colnames(iris[5])}`")   # glue object

class(my_str)
[1] "glue"      "character"

eval(parse_expr(my_str)) %>% as.factor

[1] setosa     setosa     setosa     setosa     setosa     setosa     setosa     setosa     setosa    
 ...
[145] virginica  virginica  virginica  virginica  virginica  virginica 
Levels: setosa versicolor virginica

字符串

赞(0）回复(0）举报 12个月前

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R语言胶水作为一个对象

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