从ls(pattern =“"“)列出列表[R] [英] Make a list from ls(pattern="") [R]

问题描述

ls(pattern =")函数对我来说非常有用，因为我的对象列表似乎在不断增长.我很好奇这个功能是否会更有用.

The ls(pattern="") function is very useful for me, since my list of objects seem to keep growing and growing. I am curious if this feature can be more useful.

例如，假设我有4个对象，

For example, let's say i have 4 objects,

a.c<-1
b.c<-2
c.c<-3
d.c<-4

现在我使用有用的 ls(pattern =")函数

ls(pattern=".c")

现在我尝试列出一个清单

Now i try to make a list

list(ls(patter=".c"))

但是它并没有给我任何有用的信息("a.c""b.c""c.c""d.c" ).我想要这两个输出之一

But it doesn't give me anything useful( "a.c" "b.c" "c.c" "d.c" ). I want either of these two outputs

1,2,3,4

OR

a.c, b.c, c.c, d.c

推荐答案

几个问题:

1) ".c" 中的 . 被忽略，你需要转义"它:

1) The . in ".c" gets ignored, you need to "escape" it:

ls(pattern="\\.c")

否则，它将返回所有带有 c 的对象，而不管其是否带有句点.

Otherwise it will return all objects with c regardless of having a period.

2) ls 返回对象的名称作为字符.要基于对象的名称获取值，您需要功能 get :

2) ls returns names of objects as character. To get the value of an object based on its name you need the function get:

lapply(ls(pattern="\\.c"), get)

3)正如joran在评论中所提到的，最好将对象彼此关联在列表中:

3) As joran mentioned in the comments, it's much better to keep objects associated with each other in lists:

List.c = list(a.c=1, b.c=2, c.c=3, d.c=4)

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