R語言中的for循環結構


 

1、

for (i in 1:10) { print("hello,world!") }

 

 

2、

for (i in 1:10) { print(i) }

 

 

3、

sum = 0
for (i in seq(1,100,1)) { sum = sum + i } print(sum)

 

 

4、求二維數組中的最大值

x<-c(11,34,12,87,89,93,54,31,88) ar<-array(x,c(3,3)) max<-ar[1,1] for(i in 1:3) { for(j in 1:3) { if (ar[i,j] > max) { max = ar[i,j] } } } print(max)

 

求三維數組的最大值

dim1 <- c("a1","a2","a3") dim2 <- c("b1","b2","b3","b4","b3") dim3 <- c("c1","c2") tmp <- sample(1:100,3*5*2) a <- array(tmp,c(3,5,2),dimnames = list(dim1,dim2,dim3)) max = a[1,1,1] for (k in 1:2) { for (j in 1:5) { for (i in 1:3) { if (a[i,j,k] > max) { max = a[i,j,k] } } } } print(max) max(tmp)

 

5、求Fibonacci序列

n <- 30 a <- c(0,1) for (i in 3:n) { a[i] = a[i - 1] + a[i - 2] } print(a)

 

6、已知Fibonacc數列為:1,1,2,3,5,8,求Fibonacc數列前50項的和

n <- 50 a <- c(1,1) sum <- a[1] + a[2] for (i in 3:n) { a[i] = a[i - 1] + a[i - 2] sum = sum + a[i] } print(sum)

 

7、處理矩陣、數據框元素

a <- matrix(1:16,4,4) a for (i in 1:nrow(a)) { for (j in 1:ncol(a)) { a[i,j] = a[i,j] * 2 } } a

 


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