lesson,1,2,3

## This is the pratice lesson 1,2,3
> x <-1
> print(x)
[1] 1
> [1]
Error: unexpected '[' in "["
> msg <-"hello"
> msg
[1] "hello"
>  ## above is string
> x <- 5
> x
[1] 5
> print(x)
[1] 5
> x <- 1:20
> x
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14
[15] 15 16 17 18 19 20
> x <- 1:50
> x
 [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14
[15] 15 16 17 18 19 20 21 22 23 24 25 26 27 28
[29] 29 30 31 32 33 34 35 36 37 38 39 40 41 42
[43] 43 44 45 46 47 48 49 50
> ## Creating Vectors
> ## The c() function be used to create vectors of objects.
> x <- c(0.5,0.6) ## numeric
> class(x)
[1] "numeric"
> x <- c(TRUE,FALSE) ## logical
> class(x)
[1] "logical"
> > x <- c(T,F) ## logical
Error: unexpected '>' in ">"
>  x <- c(TRUE,FALSE) ## logical
> class(x)
[1] "logical"
> x <- c("a","b","c") ## character
> class(x)
[1] "character"
> x <- 9:29  ##integer
> class(x)
[1] "integer"
> x <- c(1+0i, 2+4i) ## complex
> class(x)
[1] "complex"
> ## Using the vectors() function
> x <- vector("numeric",length = 10)
> x
 [1] 0 0 0 0 0 0 0 0 0 0
> ## Mixing Objects 
> ## what about the following?
> y <- c(1.7, "a")  ## character
> class(y)
[1] "character"
> y <-c(TRUE,2)
> y
[1] 1 2
> class(y)
[1] "numeric"
> y <-c("a",TRUE)
> class(y)
[1] "character"
> ## Explicit Corecion
> ## objects can be explicitly corecred from one class to another using the 
> x <- 0:6
> class(x)
[1] "integer"
> 
> as.numeric(x)
[1] 0 1 2 3 4 5 6
> as.numeric(x) ## one data type change another data type
[1] 0 1 2 3 4 5 6
> as.character(x)
[1] "0" "1" "2" "3" "4" "5" "6"
> as.logical(x)
[1] FALSE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
> EXplicit Corecion
Error: unexpected symbol in "EXplicit Corecion"
> ##  EXplicit Corecion
> ## Nonsensical corecion results in NAs.
> x <- c("a","b","c")
> 
> as.numeric(x)
[1] NA NA NA
Warning message:
NAs introduced by coercion 
> 
> as.logical(x)
[1] NA NA NA
> x <- 0:6
> 
> as.complex(x)
[1] 0+0i 1+0i 2+0i 3+0i 4+0i 5+0i 6+0i