为什么数字没有映射到每一行？

Question

因此，我尝试查找另一个数据集中每个名称的出现次数。我尝试运行的代码是：

Data$Count <- grep(Data$Name,OtherDataSet$LeadName) %>% length()

问题是当我运行此命令时，名字的编号将映射到该列中的每个位置。为什么会这样？

Answer 1

library(tidyverse)
Data <- data_frame(Name=c("Dog","Cat","Bird"))
OtherDataSet <- data_frame(LeadName=c("Frog","Cat","Catfish","BirdOfPrey","Bird","Bird"))
Data <- Data %>% mutate(Count=map(.x = Name,~str_detect(.,pattern = OtherDataSet$LeadName)) %>% map_int(~sum(.)))