引导程序或列表的呼叫名称

Question

I have a vector named "vec". I label the elements from "a" to "m"

vec <- c(1,1,1,2,2,2,2,2,2,4,4,4,4)
names(vec) <- c("a","b","c","d","e","f","g","h","i","j","k","l","m")

Then I split the vec according to the sequences.

split_vec <- split(vec, vec)

Now when I type Spec_vec$"1" I get the first list.

Instead of typing the specific name as "1". I want to get the values such as

spec_vec$vec[1] But the above function doesn't work. Is there a way to get that?

Answer 1

You can do

split_vec[[as.character(vec[1])]]
# a b c 
# 1 1 1 

Notice that you need as.character , since just the number value from vec[i] would give incorrect results for calls like split_vec[[vec[10]]] where you would expect the third element.

split_vec[[vec[10]]]
# Error in split_vec[[vec[10]]] : subscript out of bounds

split_vec[[as.character(vec[10])]]
# j k l m 
# 4 4 4 4 

But in general, it's best to avoid such names that begin with numerics because, obviously, it's quite awkward and can cause trouble.