我想在一些字符串之后获取值，演示如下
dt <- data.table(col.1 = c("a1, b2, c3, d4"))
x <- c("a", "b", "c")
dt[, (x) := lapply(FUN = str_match(string = .SD,
pattern = paste0("(?<=", x, ")([\\d])"))[, 2],
X = x),
.SDcols = "col.1"]
理想的结果看起来像这样
desirable <- data.table(col.1 = c("a1, b2, c3, d4"),
a = c("1"),
b = c("2"),
c = c("3"))
我收到如下错误消息：
*match.fun(FUN) 中的错误：
c("'str_match(string = .SD, pattern = paste0(\"(?<=\", x, \")([\\\\d])\"))[, ' is not a function, character or symbol", "' 2]' is not a function, character or symbol")* …我有一张表格，其中描述了如下症状：
DT <- data.table(no = c(1, 2, 3),
symptom = c("headache and numbness", "tachycardia, sometimes headahce", "breath difficulty with limb numbness"))
我关注的关键词是这样的
key.word <- list(
head = c("head", "headache"),
chest = c("breath", "tachycardia", "palpitaion")
我想添加两列来描述变量中是否提到了该关键字症状，理想的结果如下所示
result <- data.table(no = c(1, 2, 3),
symptom = c("headache and numbness", "tachycardia, sometimes headahce", "breath difficulty with limb numbness"),
head = c(T, T, F),
chest = c(F, T, T))
我可以通过以下方式完成这项工作
DT[symptom %like% paste0(head, collapse = "|"), head := T]
DT[symptom %like% paste0(chest, …