1 ## 1
   2 # 33. Try to use R as a calculator: What is greater exp(pi) oder pi^e.
   3 exp(pi) > pi**exp(1)
   4 
   5 max(c(exp(pi),pi**exp(1)))
   6 
   7 which.max(c(exp(pi),pi**exp(1)))
   8 
   9 
  10 
  11 
  12 
  13 
  14 
  15 
  16 
  17 
  18 ## 3
  19 # 1 Create a vector w with components 1, -1, 2, -2
  20 (w <- c(1,-1,2,-2)) # or
  21 (w <- rep(c(1,2),c(2,2)) * c(1,-1)) ## just interesting if you want to create a vector like this
  22 # 2
  23 w
  24 # 3
  25 str(w)
  26 # 4
  27 w + 1
  28 # 5
  29 v <- c(0,1,seq(5,75,by=5))
  30 # 6
  31 length(v)
  32 
  33 ## 3
  34 x <- c(2, 7, 0, 9, 10, 23, 11, 4, 7, 8, 6, 0)
  35 x[4]
  36 x[3:5]
  37 x[c(1, 5, 8)]
  38 
  39 x > 10
  40 i <- x > 10
  41 x[x > 10]
  42 
  43 x[i]
  44 
  45 i <- (1:6) * 2
  46 x[(1:6) * 2]
  47 x[i]
  48 
  49 x == 0
  50 x[x == 0] <- 1
  51 x
  52 
  53 round(x/2) == x/2
  54 
  55 ifelse(round(x/2) == x/2, "even", "odd")
  56 
  57 # 3 part 2
  58 # using a numeric index
  59 (i <- seq(3,length(x),by=3))
  60 (i <- c(3,6,9,12))
  61 (i <- (1:4)*3)
  62 
  63 x[seq(3,length(x),by=3)]
  64 x[i]
  65 
  66 # using logic index
  67 (i <- c(1:length(x)) %% 3 == 0)
  68 x[i]
  69 
  70 # 2
  71 (i <- x > 4 & x < 10)
  72 x[i]
  73 
  74 # 3
  75 (i <- x > 10)
  76 x[i] <- 10
  77 x ## or shorter
  78 x[x > 10] <- 10
  79 
  80 # 4
  81 (i <- x < 5)
  82 x[i] <- x[i]*2
  83 
  84 x[x < 5] <- x[x < 5]*2
  85 
  86 x <- ifelse(x < 5,x*2,x)
  87 
  88 # 5
  89 y <- rep(0:1,6)
  90 
  91 (z1 <- ifelse(y==0,x,3*x))
  92 
  93 (z2 <- x+x*y*2)
  94 
  95 (z3 <- x*(1+y*2))
  96 
  97 
  98 ### 3.2
  99 load("presidential.rdata")
 100 presidential
 101 
 102 ## 1
 103 presidential[presidential$party=="Republican",]
 104 
 105 ## 2
 106 presidential[presidential$party=="Democratic",]
 107 
 108 ## 3
 109 presidential[presidential$duration > 3 & presidential$duration < 6,]
 110 
 111 ## 4
 112 #### table
 113 table(presidential$party)
 114 
 115 ### true of duration max (8)
 116 presidential$durmax <- presidential$duration==8
 117 
 118 #### table party - durmax
 119 table(presidential$party,presidential$durmax)
 120 
 121 
 122 ####
 123 load("201404zeiten.rdata")
 124 
 125 head(t098)
 126 names(t098)
 127 summary(t098)
 128 
 129 
 130 t098$dauer <- t098$ENDE - t098$BEGINN
 131 
 132 t098$dauer <- as.numeric(t098$ENDE - t098$BEGINN)/60
 133 
 134 t098$dauer[t098$dauer > 60] <- NA
 135 
 136 
 137 summary(t098)
 138 
 139 hist(t098$dauer)
 140