xstr_length(x)#检测字符串内的字符数,空格也算length(x)#向量里面元素的个数2.字符串拆分str_split(x," ")#以空格为分隔符号将字符串拆分开x2 = str_split...distinct(test,Species,.keep_all = T)#.keep_all意思是把所有列都保存下来mutate,数据框新增一列mutate(test, new = Sepal.Length...() %>% #转换为数据框架 rownames_to_column() %>% #把行名变为正式的一列 mutate(group = rep(c("control","treat"),each =...FUN是函数test<- iris[1:6,1:4]apply(test, 2, mean)apply(test, 1, sum)#2.lapply(list, FUN, …) # 对列表/向量中的每个元素...(向量)实施相同的操作test <- list(x = 36:33,y = 32:35,z = 30:27);test#返回值是列表,对列表中的每个元素(向量)求均值(试试方差var,分位数quantile