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...,"o","A")6.字符删除xstr_remove(x," ")#默认只删第一个str_remove_all(x," ")#专题二：玩转数据框test <- iris[c(1:2,51:52,101:...) #从小到大arrange(test, desc(Sepal.Length)) #从大到小，没有increasedistinct，数据框按照某一列去重复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 * Sepal.Width)连续的步骤# 1.多次赋值，...，6列的矩阵exp = round(exp,2)#保留小数点后两位rownames(exp) = paste0("gene",1:3)colnames(exp) = paste0("test",1:6)
