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symnum: Symbolic Number Coding

symnum

R Documentation

Symbolic Number Coding

Description

Symbolically encode a given numeric or logical vector or array. Particularly useful for visualization of structured matrices, e.g., correlation, sparse, or logical ones.

Usage

symnum(x, cutpoints = c(0.3, 0.6, 0.8, 0.9, 0.95),
       symbols = if(numeric.x) c(" ", ".", ",", "+", "*", "B")
                 else c(".", "|"),
       legend = length(symbols) >= 3,
       na = "?", eps = 1e-5, numeric.x = is.numeric(x),
       corr = missing(cutpoints) && numeric.x,
       show.max = if(corr) "1", show.min = NULL,
       abbr.colnames = has.colnames,
       lower.triangular = corr && is.numeric(x) && is.matrix(x),
       diag.lower.tri   = corr && !is.null(show.max))

Arguments

`x`	numeric or logical vector or array.
`cutpoints`	numeric vector whose values `cutpoints[j]` == c[j] (after augmentation, see `corr` below) are used for intervals.
`symbols`	character vector, one shorter than (the augmented, see `corr` below) `cutpoints`. `symbols[j]` == s[j] are used as ‘code’ for the (half open) interval (c[j], c[j+1]]. When `numeric.x` is `FALSE`, i.e., by default when argument `x` is `logical`, the default is `c(".","\|")` (graphical 0 / 1 s).
`legend`	logical indicating if a `"legend"` attribute is desired.
`na`	character or logical. How `NAs` are coded. If `na == FALSE`, `NA`s are coded invisibly, including the `"legend"` attribute below, which otherwise mentions NA coding.
`eps`	absolute precision to be used at left and right boundary.
`numeric.x`	logical indicating if `x` should be treated as numbers, otherwise as logical.
`corr`	logical. If `TRUE`, `x` contains correlations. The cutpoints are augmented by `0` and `1` and `abs(x)` is coded.
`show.max`	if `TRUE`, or of mode `character`, the maximal cutpoint is coded especially.
`show.min`	if `TRUE`, or of mode `character`, the minimal cutpoint is coded especially.
`abbr.colnames`	logical, integer or `NULL` indicating how column names should be abbreviated (if they are); if `NULL` (or `FALSE` and `x` has no column names), the column names will all be empty, i.e., `""`; otherwise if `abbr.colnames` is false, they are left unchanged. If `TRUE` or integer, existing column names will be abbreviated to `abbreviate(*, minlength = abbr.colnames)`.
`lower.triangular`	logical. If `TRUE` and `x` is a matrix, only the lower triangular part of the matrix is coded as non-blank.
`diag.lower.tri`	logical. If `lower.triangular` and this are `TRUE`, the diagonal part of the matrix is shown.

Value

An atomic character object of class noquote and the same dimensions as x.

If legend is TRUE (as by default when there are more than two classes), the result has an attribute "legend" containing a legend of the returned character codes, in the form

c[1] \sQuote{s[1]} c[2] \sQuote{s[2]} … \sQuote{s[n]} c_[n+1]

where c[j] = cutpoints[j] and s[j] = symbols[j].

Note

The optional (mostly logical) arguments all try to use smart defaults. Specifying them explicitly may lead to considerably improved output in many cases.

Author(s)

Martin Maechler maechler@stat.math.ethz.ch

Examples

ii <- setNames(0:8, 0:8)
symnum(ii, cutpoints =  2*(0:4), symbols = c(".", "-", "+", "$"))
symnum(ii, cutpoints =  2*(0:4), symbols = c(".", "-", "+", "$"), show.max = TRUE)

symnum(1:12 %% 3 == 0)  # --> "|" = TRUE, "." = FALSE  for logical

## Pascal's Triangle modulo 2 -- odd and even numbers:
N <- 38
pascal <- t(sapply(0:N, function(n) round(choose(n, 0:N - (N-n)%/%2))))
rownames(pascal) <- rep("", 1+N) # <-- to improve "graphic"
symnum(pascal %% 2, symbols = c(" ", "A"), numeric.x = FALSE)

##-- Symbolic correlation matrices:
symnum(cor(attitude), diag.lower.tri = FALSE)
symnum(cor(attitude), abbr.colnames = NULL)
symnum(cor(attitude), abbr.colnames = FALSE)
symnum(cor(attitude), abbr.colnames = 2)

symnum(cor(rbind(1, rnorm(25), rnorm(25)^2)))
symnum(cor(matrix(rexp(30, 1), 5, 18))) # <<-- PATTERN ! --
symnum(cm1 <- cor(matrix(rnorm(90) ,  5, 18))) # < White Noise SMALL n
symnum(cm1, diag.lower.tri = FALSE)
symnum(cm2 <- cor(matrix(rnorm(900), 50, 18))) # < White Noise "BIG" n
symnum(cm2, lower.triangular = FALSE)

## NA's:
Cm <- cor(matrix(rnorm(60),  10, 6)); Cm[c(3,6), 2] <- NA
symnum(Cm, show.max = NULL)

## Graphical P-values (aka "significance stars"):
pval <- rev(sort(c(outer(1:6, 10^-(1:3)))))
symp <- symnum(pval, corr = FALSE,
               cutpoints = c(0,  .001,.01,.05, .1, 1),
               symbols = c("***","**","*","."," "))
noquote(cbind(P.val = format(pval), Signif = symp))