提取3位数字,我有以下数据ř只有从字符串
data <- data.frame(make=c("af455f5","255tfd4d3","ojt100","12unin234mimo24","sh469dh","6ht6k778k9","kjh457"),
type=c("a","a","a","a","b","a","b"))
我只希望从“制造”的元素中提取任何三位数如果相应的类型是“A”。
我试过使用gsub,但似乎只能提取组合字符串中的所有数字。
我在寻找的结果如下
result <- c("455","255","100","234","778")