的聚合列我有一個data.frame看起來像這樣R:一個data.frame
> head(df)
Memory Memory Memory Memory Memory Naive Naive
10472501 6.075714 5.898929 6.644946 6.023901 6.332126 8.087944 7.520194
10509163 6.168941 6.495393 5.951124 6.052527 6.404401 7.152890 8.335509
10496091 10.125575 9.966211 10.075613 10.310952 10.090649 11.803949 11.274480
10427035 6.644921 6.658567 6.569745 6.499243 6.990852 8.010784 7.798154
10503695 8.379494 8.153917 8.246484 8.390747 8.346748 9.540236 9.091740
10451763 10.986717 11.233819 10.643245 10.230697 10.541396 12.248487 11.823138
,我想找到Memory
列的平均值和Naive
列的平均值。 aggregate
函數聚合行。這data.frame
可能有大量行,因此調換然後通過初始data.frame
的colnames
應用aggregate
給我的印象不好,而且一般是煩人:
> head(t(aggregate(t(df),list(colnames(df)), mean)))
[,1] [,2]
Group.1 "Memory" "Naive"
10472501 "6.195123" "8.125439"
10509163 "6.214477" "7.733625"
10496091 "10.11380" "11.55348"
10427035 "6.672665" "8.266854"
10503695 "8.303478" "9.340436"
什麼是我錯過了言自明的事情?
敏銳的眼睛中,你會發現,8.12不是8.08和7.52的意思是:有一些更多的列事實上。雖然沒有更多! – 2010-07-27 22:44:17