Subunit in the curve

Usage

# S3 method for sfc_nxn
[(x, i, j, ..., drop = TRUE)

# S4 method for sfc_nxn
sfc_index(p, index = "")

Arguments

x: An sfc_nxn object.
i, index: A string of digits representing the path on the hierarchy of the curve. The left side corresponds to the top level and the right side corresponds to the bottom level on the curve. For the 2x2 curve, the digits can only be 1-4, and for the Peano and Meander curves, the digites can be 1-9. The hierarchical index should be specified in a format of i1:i2:i3:... where : can be replaced by any non-number character. For 2x2 and 3x3 curves, : can be omitted and the hierarchical index can be specified as i1i2i3.... See the Examples section.
j: A value of TRUE or FALSE that controls whether to keep the sfc_nxn class or degenerate to the sfc_sequence class.
...: Ignore.
drop: A value of TRUE or FALSE that controls whether to keep the sfc_nxn class or degenerate to the sfc_sequence class.
p: An sfc_nxn object.

Details

sfc_index() only works on square curves (i.e. a curve with a single base letter as seed.)

Examples

p = sfc_2x2("I", "11111")
p["3:2:1"]
#> A sequence of 16 base patterns.
#>   I(270)L(270)L(0)R(90)   I(0)R(0)R(270)L(180)
#>   L(270)R(0)R(270)I(180)  R(180)L(90)L(180)I(270)
# for 2x2 and 3x3 curves, ":" can be omitted
p["321"]
#> A sequence of 16 base patterns.
#>   I(270)L(270)L(0)R(90)   I(0)R(0)R(270)L(180)
#>   L(270)R(0)R(270)I(180)  R(180)L(90)L(180)I(270)
p["3:2:1", TRUE] # or p["3:2:1", drop = FALSE]
#> An sfc_2x2 object.
#>   Increase mode: 2 x 2
#>   Level: 5
#>   Expansion rule: 2x2 
#>   A fragment from the original curve.
#> 
#> A sequence of 16 base patterns.
#>   I(270)L(270)L(0)R(90)   I(0)R(0)R(270)L(180)
#>   L(270)R(0)R(270)I(180)  R(180)L(90)L(180)I(270)
#> 
#> Seed: A sequence of 1 base pattern.
#>   I(0)  
# only for testing
p = sfc_2x2("I", "11111")
om = par(no.readonly = TRUE)
par(mfrow = c(2, 2))
sfcurve:::test_sfc_index(p, "3")
sfcurve:::test_sfc_index(p, "3:2")
sfcurve:::test_sfc_index(p, "3:2:1")
sfcurve:::test_sfc_index(p, "3:2:1:1")

par(om)

p = sfc_3x3_meander("I", "11111")
om = par(no.readonly = TRUE)
par(mfrow = c(2, 2))
sfcurve:::test_sfc_index(p, "7")
sfcurve:::test_sfc_index(p, "7:5")
sfcurve:::test_sfc_index(p, "7:5:9")
sfcurve:::test_sfc_index(p, "7:5:9:2")

par(om)