shift {StratigrapheR}

Circular shift

Description

Circular shift; the order of points will be lagged as if the beginning is preceded by the end.

Usage

shift(x, n = 1L, p = -n + 1L, i = NA, names = T)

Arguments

x

a vector (characters, numerics, integers,...), data.frame or list

n

a positive integer of length 1, giving the number of positions to shift by (positive values generate lag)

p

the index position or row that will become the first one (overrides n)

i

a vector of ids to divide x in various groups; the shift will occur on the subgroups defined by identical i ids.

names

whether the names of the elements or rows should also shift

Value

the same object than the input, but with a shifted order

Examples

# Simple use ----------------------------------------------------------------

shift(x = c(6,8,10,12,2,4), n = 2)

#> [1]  2  4  6  8 10 12

vector        <- rep(1:4, 3)
names(vector) <- rep(c("P1", "P2", "P3"), each = 4)
split(vector, f = names(vector))

#> $P1
#> P1 P1 P1 P1
#>  1  2  3  4
#>
#> $P2
#> P2 P2 P2 P2
#>  1  2  3  4
#>
#> $P3
#> P3 P3 P3 P3
#>  1  2  3  4

sh <- shift(x = vector, i = names(vector), p = c(1,2,3))
split(sh, f = names(sh))

#> $P1
#> P1 P1 P1 P1
#>  1  2  3  4
#>
#> $P2
#> P2 P2 P2 P2
#>  2  3  4  1
#>
#> $P3
#> P3 P3 P3 P3
#>  3  4  1  2

# Applications to litholog generation ---------------------------------------

l <- c(1,2,3)
r <- c(0,1,2)
h  <- c(4,3,4)
i   <- c("B1","B2","B3")

basic.litholog <- litholog(l,r,h,i)

whiteSet(xlim = c(0,4), ylim = c(0,3),
         xaxs = "r", yaxs = "r",   # This gives a little room to the graph
         ytick = 1, ny = 10)

multigons(basic.litholog$i, basic.litholog$xy, basic.litholog$dt,
          forget = "B1", lwd = 2)

openbed <- subset(basic.litholog, basic.litholog == "B1")

openbed <- shift(openbed, -1)

lines(openbed$xy, openbed$dt, lwd = 2)