R计算data.frame行row平均方法

R计算data.frame行row平均方法有2种 rowMeans()和apply()：

创建data.frame,计算平均分Avg_score

df1 = data.frame( Name = c('George','Andrea', 'Micheal','Maggie','Ravi','Xien','Jalpa'), 
 Mathematics1_score=c(62,47,55,74,32,77,86),
 Mathematics2_score=c(45,78,44,89,66,49,72),
 Science_score=c(56,52,45,88,33,90,47))
计算方法如下

方法1.rowMeans() 

df1$Avg_score = rowMeans(df1[,c(2,3,4)])
方法2.apply()

df1$Avg_score = apply(df1[,-1], 1, mean)