提取3位數字,我有以下數據ř只有從字符串
data <- data.frame(make=c("af455f5","255tfd4d3","ojt100","12unin234mimo24","sh469dh","6ht6k778k9","kjh457"),
type=c("a","a","a","a","b","a","b"))
我只希望從「製造」的元素中提取任何三位數如果相應的類型是「A」。
我試過使用gsub,但似乎只能提取組合字符串中的所有數字。
我在尋找的結果如下
result <- c("455","255","100","234","778")