dplyr包
- mutate(),将一列向量加入到已有的数据框,向量长度和数据框列数要一样
- select(),选择数据框的某几列
- filter(),对数据框的行进行筛选
df1 <- data.frame(
name = c("Alice", "Alice", "Bob", "Bob", "Carol", "Carol"),
type = c("english", "math", "english", "math", "english", "math")
)
## mutate()
df2<-mutate(df1, newcol=c(60, 85, 70, 75, 85, 90))
## select()
select(df2, name, newcol)
select(df2, !newcol)
## filter()
filter(newcol>75) #比如筛选newcol大于75的行
filter(type=="english",newcol>75) #只看英语成绩大于75
https://bookdown.org/wangminjie/R4DS/dplyr.html
grep
target <- row.names(s1dat)[grep("fore", s1dat$mark)]
"=="
d$ccc[d$node==nodeid(s1tree,target)]<-"red"