(macOS)[R] 반복문 : for, while | 조건문 : if/else | 사용자 정의 함수 : function()

INTRO

1. 반복문 : iterational code block

2. 조건문 : conditional code block

3. 사용자 정의 함수 : costomized function

 

 

1. 반복문

for

 for (i in range) {

 print(i)

 }

 

while

 x = 1

 while ( x<num) {

 x = x + 1

 print(x)

 }

 

2. 조건문

if/else

 if (condition) restult_1

 else results_2

 

 

test_iterational_conditional_code_block.R

rm(list = ls())
setwd("/Users/[YourMacID]/Rcoding")

## for
a = c()
for (i in 1:9) {
  a[i] = i * i
  cat("i = ",i)
  cat(" | a = ",a)
  cat("\n")
}

## for
isum = 0
for (i in 1:100) {
  isum = isum + i
}
print(isum)
cat("summation of 1 to 100 is ",isum,"\n")


## while
x = 1
while (x < 5) {
  print(x)
  x = x + 1
}


## if
rand_a = sample(x=1:100, size=40)
over50 = rep(0.40)
for(i in 1:40) {
  if (rand_a[i] >= 50) over50[i] = 1
  else over50[i] = 0
}
print(rand_a)
print(over50)
cat("count for results : ",sum(over50),"\n")

 

출력결과

> source("~/Rcoding/test_conditional_code_block.R", echo=TRUE)

> rm(list = ls())

> # setwd("/Users/[YourMacID]/Rcoding")
> setwd("/Users/jiwonlee/Rcoding")

> ## for
> a = c()

> for (i in 1:9) {
+   a[i] = i * i
+   cat("i = ",i)
+   cat(" | a = ",a)
+   cat("\n")
+ }
i =  1 | a =  1
i =  2 | a =  1 4
i =  3 | a =  1 4 9
i =  4 | a =  1 4 9 16
i =  5 | a =  1 4 9 16 25
i =  6 | a =  1 4 9 16 25 36
i =  7 | a =  1 4 9 16 25 36 49
i =  8 | a =  1 4 9 16 25 36 49 64
i =  9 | a =  1 4 9 16 25 36 49 64 81

> ## for
> isum = 0

> for (i in 1:100) {
+   isum = isum + i
+ }

> print(isum)
[1] 5050

> cat("summation of 1 to 100 is ",isum,"\n")
summation of 1 to 100 is  5050 

> ## while
> x = 1

> while (x < 5) {
+   print(x)
+   x = x + 1
+ }
[1] 1
[1] 2
[1] 3
[1] 4

> ## if
> rand_a = sample(x=1:100, size=40)

> over50 = rep(0.40)

> for(i in 1:40) {
+   if (rand_a[i] >= 50) over50[i] = 1
+   else over50[i] = 0
+ }

> print(rand_a)
 [1]  95  85  70   7  49  78   2 100  21  66  12  93  34  43  50  51  99  65  86  63  79  52   1  37  69  80  59
[28]  39   8  71  62  53  77  16  58   4  14  35  96  56

> print(over50)
 [1] 1 1 1 0 0 1 0 1 0 1 0 1 0 0 1 1 1 1 1 1 1 1 0 0 1 1 1 0 0 1 1 1 1 0 1 0 0 0 1 1

> cat("count for results : ",sum(over50),"\n")
count for results :  25

 

 

3.  사용자 정의 함수

fun_name = function(args) {

code_blocks

}

test_costomized_function.R

rm(list = ls())
setwd("/Users/[YourMacID]/Rcoding")

## define function
addto = function(x) {
  isum = 0
  for (i in 1:x) {
    isum = isum + i
  }
  print(isum)
}

addto(100)
addto(50)

 

출력결과

> source("~/Rcoding/test_costomized_function.R", echo=TRUE)

> rm(list = ls())

> setwd("/Users/[YourMacID]/Rcoding")

> ## define function
> addto = function(x) {
+   isum = 0
+   for (i in 1:x) {
+     isum = isum + i
+   }
+   print(isum)
+ }

> addto(100)
[1] 5050

> addto(50)
[1] 1275