R 按两列重新排列数据帧

如何通过降低列

value

中值的顺序排列数据帧，其中列

中的值“cat”=X

数据帧

df1<-data.frame(group=rep(c("A", "B", "C", "D"),each=2), cat=rep(c("X", "Y"),4), value=c(1,0.6,1,0.5,1,2,1,5))

---

df1由于
cat'x'
的
value
总是相同的，我们可以按
group
对
值进行求和，然后使用该值对数据进行排序

# Create data.frame
df1<-data.frame(group=rep(c("A", "B",   "C", "D"),each=2), 
                cat=rep(c("X", "Y"),4), 
                value=c(1,0.6,1,0.5,1,2,1,5))
# Sum values by group (since x is same...)
df2 <- aggregate(df1$value,   by=list(group=df1$group), FUN=sum)

# Join tables
library(plyr)
output <- join(df1, df2, by='group', type='left', match='all')

# Sort
output <- output[with(output, order(-x, cat)),] 

@Pyl dupe中唯一缺失的部分是OP需要重新排列系数
组
，即
df1$组的级别
# Limit to only cat=Y
df2 <- df1[which(df1$cat=='Y'),]

# Order by descending
df2 <- df2[order(-df2$value),]

# Create a vector based on group column
order_vector <- df2[,'group']

# Use vector from above to designate new factor levels
df1$group <- factor(df1$group, levels = order_vector)

# Sort
output2 <- df1[with(df1, order(group, cat)), ]