h-elena

paste(letters[1:5], as.character(1:5))
[1] "a 1" "b 2" "c 3" "d 4" "e 5"
> paste(letters[1:5], as.character(1:3))
[1] "a 1" "b 2" "c 3" "d 1" "e 2"
> expand.grid(pants = c("blue", "black"), shirt = c("white", "grey", "plaid")) # 모든 조합 생성?
  pants shirt
1  blue white
2 black white
3  blue  grey
4 black  grey
5  blue plaid
6 black plaid



> install.packages("gtools")
> library(gtools)
> permutations(5,2)
      [,1] [,2]
 [1,]    1    2
 [2,]    1    3
 [3,]    1    4
 [4,]    1    5
 [5,]    2    1
 [6,]    2    3
 [7,]    2    4
 [8,]    2    5
 [9,]    3    1
[10,]    3    2
[11,]    3    4
[12,]    3    5
[13,]    4    1
[14,]    4    2
[15,]    4    3
[16,]    4    5
[17,]    5    1
[18,]    5    2
[19,]    5    3
[20,]    5    4
> combinations(5,2)
      [,1] [,2]
 [1,]    1    2
 [2,]    1    3
 [3,]    1    4
 [4,]    1    5
 [5,]    2    3
 [6,]    2    4
 [7,]    2    5
 [8,]    3    4
 [9,]    3    5
[10,]    4    5

> all_phone_numbers <- permutations(10, 7, v = 0:9)
> n <- nrow(all_phone_numbers)
> n
[1] 604800
> index <- sample(n, 5)
> index
[1] 124574 106782 415511 232305 465598
> all_phone_numbers[index,]
     [,1] [,2] [,3] [,4] [,5] [,6] [,7]
[1,]    2    0    6    4    1    8    5
[2,]    1    7    9    0    8    2    4
[3,]    6    8    7    4    3    2    5
[4,]    3    8    5    4    9    1    0
[5,]    7    6    2    1    9    8    3

> suits <- c("d", "c", "h", "s")
> numbers <- c("a", "j", "q", "k", as.character(1:10))
> deck <- expand.grid(number=numbers, suit=suits)
> deck<-paste(deck$number, deck$suit)
> deck
 [1] "a d"  "j d"  "q d"  "k d"  "1 d"  "2 d" 
 [7] "3 d"  "4 d"  "5 d"  "6 d"  "7 d"  "8 d" 
[13] "9 d"  "10 d" "a c"  "j c"  "q c"  "k c" 
[19] "1 c"  "2 c"  "3 c"  "4 c"  "5 c"  "6 c" 
[25] "7 c"  "8 c"  "9 c"  "10 c" "a h"  "j h" 
[31] "q h"  "k h"  "1 h"  "2 h"  "3 h"  "4 h" 
[37] "5 h"  "6 h"  "7 h"  "8 h"  "9 h"  "10 h"
[43] "a s"  "j s"  "q s"  "k s"  "1 s"  "2 s" 
[49] "3 s"  "4 s"  "5 s"  "6 s"  "7 s"  "8 s" 
[55] "9 s"  "10 s"
> kings<-paste("k", suits)
> kings
[1] "k d" "k c" "k h" "k s"
> mean(deck %in% kings)
[1] 0.07142857

> hands <- permutations(52, 2, v=deck) #deck 중에서 2개씩 뽑기
> nrows(hands)
[1] 2652
> first_card <- hands[,1] #first column
> second_card <- hands[,2]
> sum(first_card %in% kings)
[1] 204
> sum(first_card %in% kings & second_card%in% kings)/sum(first_card %in% kings)
[1] 0.05882353

> combinations(3,2)
     [,1] [,2]
[1,]    1    2
[2,]    1    3
[3,]    2    3

> beads<-rep(c("red","blue"), 3)
> beads
[1] "red"  "blue" "red"  "blue" "red"  "blue"

> beads<-rep(c("red","blue"), times=c(2,3))
> beads
[1] "red"  "red"  "blue" "blue" "blue"

> sample(beads, 1)
[1] "blue"

> A<-10000
> events<-replicate(A, sample(beads, 1))
> table(events)
events
blue  red 
5967 4033 
> prop.table(table(events))
events
  blue    red 
0.5967 0.4033 

> events<-replicate(100000, sample(beads, 1))
> prop.table(table(events))
events
   blue     red 
0.59903 0.40097 

> events<-replicate(100, sample(beads, 1))
> prop.table(table(events))
events
blue  red 
0.55 0.45 

> events<-sample(beads, A, replace = TRUE)
> prop.table(table(events))
events
  blue    red 
0.5999 0.4001 

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