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使用用 rowSums() 函数可以加载行资料，而 colSums() 函数可以加载列资料。

> set.seed(123) > ice_cream <- matrix(round(runif(15) * 100), nrow = 5)
> colnames(ice_cream) <- c("Vanilla", "Chocolate", "Strawberry") 
> rownames(ice_cream) <- c("Mon", "Tue", "Wed", "Thu", "Fri")
 
> ice_cream     Vanilla Chocolate Strawberry Mon      
29 5 96 Tue      79 53 45 Wed      41 89 68 Thu      88 55 57 Fri      94 46 10 

我們可以利用 rowSums() 計算每天總共賣出多少冰淇淋，也可以利用 colSums() 計算每種口味的總銷量為何。

> set.seed(123) 
> ice_cream <- matrix(round(runif(15) * 100), nrow = 5)
> colnames(ice_cream) <- c("Vanilla", "Chocolate", "Strawberry")
> rownames(ice_cream) <- c("Mon", "Tue", "Wed", "Thu", "Fri") 
> rowSums(ice_cream)
 Mon Tue Wed Thu Fri  130 177 198 200 150 
> colSums(ice_cream)    
Vanilla  Chocolate Strawberry         331 248 276 

我们亦可以利用 cbind() 将列加载的結果加入原本的資料中。

> set.seed(123) 
> ice_cream <- matrix(round(runif(15) * 100), nrow = 5) 
> colnames(ice_cream) <- c("Vanilla", "Chocolate", "Strawberry") 
> rownames(ice_cream) <- c("Mon", "Tue", "Wed", "Thu", "Fri") 
> ice_cream <- cbind(ice_cream, Totals = rowSums(ice_cream)) 
> ice_cream    
 Vanilla Chocolate Strawberry Totals Mon      
29 5 96 130 Tue      79 53 45 177 Wed      41 89 68 198 Thu      88 55 57 200 Fri      94 46 10 150 

利用 rbind() 将加载的結果也加入。

> set.seed(123) > ice_cream <- matrix(round(runif(15) * 100), nrow = 5) 
> colnames(ice_cream) <- c("Vanilla", "Chocolate", "Strawberry") 
> rownames(ice_cream) <- c("Mon", "Tue", "Wed", "Thu", "Fri") 
> ice_cream <- cbind(ice_cream, Totals = rowSums(ice_cream)) 
> ice_cream <- rbind(ice_cream, Totals = colSums(ice_cream)) 
> ice_cream        Vanilla Chocolate Strawberry Totals Mon       
  29 5 96 130 Tue         79 53 45 177 Wed         41 89 68 198 Thu         88 55 57 200 Fri         94 46 10 150 Totals     331 248 276 855