19 r judgment control function exercise

> x=rnorm(1,3,1)
> if(x>3) y=1 else y=0
> y
[1] 1
> ifelse(rbinom(10,1,0.5)," word "," flowers ")
 [1] " flowers " " word " " flowers " " word " " flowers " " word " " word " " flowers " " word " " flowers "
> set.seed(1)
> x=c("A","B","C","A","D")
> ifelse(x=="C"," no ",ifelse(x=="D",NA," yes "))# Can only replace 
[1] " yes " " yes " " no " " yes " NA  
> for (i in x) {# Traversal substitution x Elements in 
+   j=match(i,x)# Return to subscript position 
+   x1=switch(i,"A"=" yes ","B"=" yes ","C"=" no ","D"="NA")
+   x[j]=x1
+   
+ }
> x
[1] " yes " " yes " " no " " yes " "NA"
> for (i in letters[1:5]) {
+   print(i)
+ }
[1] "a"
[1] "b"
[1] "c"
[1] "d"
[1] "e"
> m=matrix(1:6,2,3)
> m
     [,1] [,2] [,3]
[1,]    1    3    5
[2,]    2    4    6
> for(i in 1:2){
+   for(j in 1:3){
+     print(m[i,j])
+   }
+ }
[1] 1
[1] 3
[1] 5
[1] 2
[1] 4
[1] 6
> j=1
> count=0
> while(count<6){
+   print(count)
+   count=count+1
+ }
[1] 0
[1] 1
[1] 2
[1] 3
[1] 4
[1] 5
> x=5
> while(x>=3 &x<10){
+   print(x)
+   x=ifelse(rbinom(10,1,0.5),x+1,x+0)
+   
+ }
[1] 5
 [1] 5 5 6 6 5 6 6 6 6 5
 [1] 5 5 7 6 6 6 7 7 6 6
 [1] 6 5 8 6 6 6 7 7 7 6
 [1] 6 6 8 6 7 7 8 7 8 6
 [1] 7 7 9 7 8 8 8 7 9 7
 [1]  7  8  9  7  8  8  8  8 10  7
 [1]  8  8  9  7  9  8  8  9 10  8
 [1]  8  9  9  7  9  9  9  9 11  9
 [1]  8 10  9  7 10  9 10  9 11  9
 [1]  8 10 10  8 11 10 10  9 12 10
 [1]  9 10 10  9 12 10 10  9 13 11
There were 12 warnings (use warnings() to see them)
> for (i in 1:20) {
+   if(i<10) next
+   print(i)
+ }
[1] 10
[1] 11
[1] 12
[1] 13
[1] 14
[1] 15
[1] 16
[1] 17
[1] 18
[1] 19
[1] 20
> loan=c("A","B","D","C","C","B","A","B","A","D")
> ifelse(loan=="D"," no ",ifelse(loan=="B","NA"," yes "))# Vector judgment substitution 
 [1] " yes " "NA" " no " " yes " " yes " "NA" " yes " "NA" " yes " " no "
> m=matrix(1:81,9,9)
> for (i in 1:9) {
+   x=1:9
+   m[i,]=x*i
+ }
> m
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
 [1,]    1    2    3    4    5    6    7    8    9
 [2,]    2    4    6    8   10   12   14   16   18
 [3,]    3    6    9   12   15   18   21   24   27
 [4,]    4    8   12   16   20   24   28   32   36
 [5,]    5   10   15   20   25   30   35   40   45
 [6,]    6   12   18   24   30   36   42   48   54
 [7,]    7   14   21   28   35   42   49   56   63
 [8,]    8   16   24   32   40   48   56   64   72
 [9,]    9   18   27   36   45   54   63   72   81
> x=as.matrix(1:9)
> y=t(as.matrix(1:9))
> m=x%*%y
> m
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
 [1,]    1    2    3    4    5    6    7    8    9
 [2,]    2    4    6    8   10   12   14   16   18
 [3,]    3    6    9   12   15   18   21   24   27
 [4,]    4    8   12   16   20   24   28   32   36
 [5,]    5   10   15   20   25   30   35   40   45
 [6,]    6   12   18   24   30   36   42   48   54
 [7,]    7   14   21   28   35   42   49   56   63
 [8,]    8   16   24   32   40   48   56   64   72
 [9,]    9   18   27   36   45   54   63   72   81
> 1:9 %*%t(1:9) # The forced conversion became 1：9 Matrix , Matrix multiplication %*%
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
 [1,]    1    2    3    4    5    6    7    8    9
 [2,]    2    4    6    8   10   12   14   16   18
 [3,]    3    6    9   12   15   18   21   24   27
 [4,]    4    8   12   16   20   24   28   32   36
 [5,]    5   10   15   20   25   30   35   40   45
 [6,]    6   12   18   24   30   36   42   48   54
 [7,]    7   14   21   28   35   42   49   56   63
 [8,]    8   16   24   32   40   48   56   64   72
 [9,]    9   18   27   36   45   54   63   72   81
> ?print
> for (i in 1:9) {#print Do not wrap , Haven't found a way , use cat Can achieve  print Vertical line printing ,cat Horizontal print 
+   for (j in 1:i) {
+     x=i*j
+     #a=paste(c(i,"*",j,"=",x," "),collapse="")
+     cat(i,"*",j,"=",x," ")
+   }
+   cat("\n")
+ }
1 * 1 = 1  
2 * 1 = 2  2 * 2 = 4  
3 * 1 = 3  3 * 2 = 6  3 * 3 = 9  
4 * 1 = 4  4 * 2 = 8  4 * 3 = 12  4 * 4 = 16  
5 * 1 = 5  5 * 2 = 10  5 * 3 = 15  5 * 4 = 20  5 * 5 = 25  
6 * 1 = 6  6 * 2 = 12  6 * 3 = 18  6 * 4 = 24  6 * 5 = 30  6 * 6 = 36  
7 * 1 = 7  7 * 2 = 14  7 * 3 = 21  7 * 4 = 28  7 * 5 = 35  7 * 6 = 42  7 * 7 = 49  
8 * 1 = 8  8 * 2 = 16  8 * 3 = 24  8 * 4 = 32  8 * 5 = 40  8 * 6 = 48  8 * 7 = 56  8 * 8 = 64  
9 * 1 = 9  9 * 2 = 18  9 * 3 = 27  9 * 4 = 36  9 * 5 = 45  9 * 6 = 54  9 * 7 = 63  9 * 8 = 72  9 * 9 = 81