Regex 在R中按单词拆分字符串

我想将字符串拆分为两个单词：

s <- "PCB153 treated HepG2 cells at T18"
strsplit(s, split = <treated><at>)

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您必须将其作为字符串输入。要在处理后进行拆分，请执行以下操作：

s <- "PCB153 treated HepG2 cells at T18"
s2 <- strsplit(s,split="treated")
unlist(s2)

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我想要三个字加两个字。

s <- "PCB153 treated HepG2 cells at T18"
s2 <- strsplit(s,split="treated")
unlist(s2)

unlist(strsplit(unlist(s2),split="at"))

strsplit(s, split="treated|at")
#[[1]]
#[1] "PCB153 "       " HepG2 cells " " T18"