1. 按照列
dat$V1[which(dat$V1 =='Repressor')] <- 'Silent'
## 将第一列是Repressor的替换为Silent
dat <- dat[grep(pattern = "chr",dat[,1]),]
## 筛选第一列是chr开头的所有行
dat$V1[which(dat$V1 =='Repressor')] <- 'Silent'
## 将第一列是Repressor的替换为Silent
dat <- dat[grep(pattern = "chr",dat[,1]),]
## 筛选第一列是chr开头的所有行