r - 在 R 中创建字符串列表

Question

假设我有一个列表 v

> v[1:5]
[1] A1CF    A2M     A2M     AADAC   AADACL3

如果我尝试创建一个新列表

x=c(v[1],v[2])

我明白了

> x
[1] 1 2

为什么 R 将整数值分配给 x，以及如何将字符串分配给新列表 x？

Answer 1

It seems that v is a vector of factors.

> v <- factor(c("A1CF", "A2M", "A2M", "AADAC", "AADACL3"))
> c(v[1],v[2])  # this reproduces your problem  
[1] 1 2
> 
> # possible alternatives. This solves your problem
> factor(c(levels(v)[1], levels(v)[2])) # Alternative 1
[1] A1CF A2M 
Levels: A1CF A2M
> factor(levels(v)[1:2])                # Alternative 2
[1] A1CF A2M 
Levels: A1CF A2M

Btw, you are dealing with a vector, not with a list.