matrix in R

> matrix(c(1,2,3,4),2,4)

     [,1] [,2] [,3] [,4]

[1,]    1    3    1    3

[2,]    2    4    2    4

> matrix(c(1,2,3,4),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    1    3    1    3    1    3    1     3     1     3

[2,]    2    4    2    4    2    4    2    4    2     4     2     4

> matrix(c(1:12),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    5    7    9   11    1    3    5     7     9    11

[2,]    2    4    6    8   10   12    2    4    6     8    10    12

> matrix(c(1:242),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    5    7    9   11   13   15   17    19    21    23

[2,]    2    4    6    8   10   12   14   16   18    20    22    24

Warning message:

In matrix(c(1:242), 2, 12) :

  data length [242] is not a sub-multiple or multiple of the number of columns [12]

> matrix(c(1:24),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    5    7    9   11   13   15   17    19    21    23

[2,]    2    4    6    8   10   12   14   16   18    20    22    24

> matrix(c(1:25),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    5    7    9   11   13   15   17    19    21    23

[2,]    2    4    6    8   10   12   14   16   18    20    22    24

Warning message:

In matrix(c(1:25), 2, 12) :

  data length [25] is not a sub-multiple or multiple of the number of rows [2]

> matrix(c(1:23),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    5    7    9   11   13   15   17    19    21    23

[2,]    2    4    6    8   10   12   14   16   18    20    22     1

Warning message:

In matrix(c(1:23), 2, 12) :

  data length [23] is not a sub-multiple or multiple of the number of rows [2]

> matrix(c(1:24),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,]    1    3    5    7    9   11   13   15   17    19    21    23

[2,]    2    4    6    8   10   12   14   16   18    20    22    24

> matrix(c("a", "b"),2,12)

     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

[1,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

[2,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

> matrix(c("a", "b"),10,12)

      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

 [1,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

 [2,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

 [3,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

 [4,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

 [5,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

 [6,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

 [7,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

 [8,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

 [9,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

[10,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

> matrix(c("a":"z"),10,12)

Error in "a":"z" : NA/NaN argument

In addition: Warning messages:

1: In matrix(c("a":"z"), 10, 12) : NAs introduced by coercion

2: In matrix(c("a":"z"), 10, 12) : NAs introduced by coercion

> matrix(c("a","b", "c", 3, "z"),10,12)

      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]

 [1,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

 [2,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

 [3,] "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"   "c"   "c"  

 [4,] "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"   "3"   "3"  

 [5,] "z"  "z"  "z"  "z"  "z"  "z"  "z"  "z"  "z"  "z"   "z"   "z"  

 [6,] "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"  "a"   "a"   "a"  

 [7,] "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"  "b"   "b"   "b"  

 [8,] "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"   "c"   "c"  

 [9,] "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"   "3"   "3"  

[10,] "z"  "z"  "z"  "z"  "z"  "z"  "z"  "z"  "z"  "z"   "z"   "z"  

> list_01 <- list("a", "b", "c", cat(1:3))

1 2 3

> list_01

[[1]]

[1] "a"

[[2]]

[1] "b"

[[3]]

[1] "c"

[[4]]

NULL

> list_01 <- list("a", "b", "c", 34)

> list_01

[[1]]

[1] "a"

[[2]]

[1] "b"

[[3]]

[1] "c"

[[4]]

[1] 34

> list_01 <- list("a", "b", "c", c(1:3))

> list_01

[[1]]

[1] "a"

[[2]]

[1] "b"

[[3]]

[1] "c"

[[4]]

[1] 1 2 3

> list_01[1]

[[1]]

[1] "a"

> list_01[4]

[[1]]

[1] 1 2 3

> list_01[4][1]

[[1]]

[1] 1 2 3

> list_01[4][2]

[[1]]

NULL

> list_02 <- list("a", "b", "c", c(1:3), ("xy"), matrix(99, 3,4) )

> list_02

[[1]]

[1] "a"

[[2]]

[1] "b"

[[3]]

[1] "c"

[[4]]

[1] 1 2 3

[[5]]

[1] "xy"

[[6]]

     [,1] [,2] [,3] [,4]

[1,]   99   99   99   99

[2,]   99   99   99   99

[3,]   99   99   99   99

> x <- 3

> y <- x*4

> z <- sqrt(x^2+y^2)

> z

[1] 12.36932

> x^2

[1] 9

> y^2

[1] 144

> list_03 <- list("a", "b", "c", c(1:3), c("jacob", "fly", "to sky"), ("xy"), matrix(99, 3,4) )

> list_03

[[1]]

[1] "a"

[[2]]

[1] "b"

[[3]]

[1] "c"

[[4]]

[1] 1 2 3

[[5]]

[1] "jacob"  "fly"    "to sky"

[[6]]

[1] "xy"

[[7]]

     [,1] [,2] [,3] [,4]

[1,]   99   99   99   99

[2,]   99   99   99   99

[3,]   99   99   99   99

> list_03[7]

[[1]]

     [,1] [,2] [,3] [,4]

[1,]   99   99   99   99

[2,]   99   99   99   99

[3,]   99   99   99   99

> list_03[7][1]

[[1]]

     [,1] [,2] [,3] [,4]

[1,]   99   99   99   99

[2,]   99   99   99   99

[3,]   99   99   99   99

> list_03[7][1][1]

[[1]]

     [,1] [,2] [,3] [,4]

[1,]   99   99   99   99

[2,]   99   99   99   99

[3,]   99   99   99   99

> list_03[7][1][1][2]

[[1]]

NULL

> list_03[7][1][1,1]

Error in list_03[7][1][1, 1] : incorrect number of dimensions

> list_03[7][1][3,4]

Error in list_03[7][1][3, 4] : incorrect number of dimensions