如何使用magicaxis使x轴成为R中以2为底的对数？

Question

Magicaxis 可让您取消记录轴：

library(magicaxis)
plot(1:10, 1:10, axes=FALSE)
magaxis(unlog='x')

但这假设一个以 10 为底的对数。你怎么能指定一个不同的基地？

Answer 1

magicaxis 的作者在这里。我的 GitHub (asgr/magicaxis) 上的新 pre-CRAN 版本具有指定日志库的新功能。您可以使用 devtools 直接从 GitHub 安装它。该参数称为 powbase，默认为 10。让我知道这对你有什么作用。

亚伦

Answer 2

调用日志或“un-log”的代码的唯一部分似乎被硬编码为使用 10^ 或函数 log10()。所以似乎没有办法告诉函数使用不同的基数。

function (side = 1:2, majorn = 5, minorn = 5, tcl = 0.5, ratio = 0.5, 
  labels = TRUE, unlog = "Auto", mgp = c(2, 0.5, 0), mtline = 2, 
  xlab = NULL, ylab = NULL, crunch = TRUE, logpretty = TRUE, 
  prettybase = 10, hersh = FALSE, family = "sans", frame.plot = FALSE, 
  usepar = FALSE, ...) 
{
  majornlist = majorn
  minornlist = minorn
  unloglist = unlog
  labelslist = labels
  crunchlist = crunch
  logprettylist = logpretty
  prettybaselist = prettybase
  if (length(majorn) == 1 & length(side) > 1) {
    majornlist = rep(majorn, length(side))
  }
  if (length(minorn) == 1 & length(side) > 1) {
    minornlist = rep(minorn, length(side))
  }
  if (length(unlog) == 1 & length(side) > 1 & (unlog[1] == 
    T | unlog[1] == F | unlog[1] == "Auto")) {
    unloglist = rep(unlog, length(side))
  }
  if (length(labels) == 1 & length(side) > 1) {
    labelslist = rep(labels, length(side))
  }
  if (length(crunch) == 1 & length(side) > 1) {
    crunchlist = rep(crunch, length(side))
  }
  if (length(logpretty) == 1 & length(side) > 1) {
    logprettylist = rep(logpretty, length(side))
  }
  if (length(prettybase) == 1 & length(side) > 1) {
    prettybaselist = rep(prettybase, length(side))
  }
  if (unlog[1] == "x") {
    unloglist = rep(FALSE, length(side))
    unloglist[side %in% c(1, 3)] = TRUE
  }
  if (unlog[1] == "y") {
    unloglist = rep(FALSE, length(side))
    unloglist[side %in% c(2, 4)] = TRUE
  }
  if (unlog[1] == "xy" | unlog[1] == "yx") {
    unloglist = rep(TRUE, length(side))
  }
  if (length(majornlist) != length(side)) {
    stop("Length of majorn vector mismatches number of axes!")
  }
  if (length(minornlist) != length(side)) {
    stop("Length of minorn vector mismatches number of axes!")
  }
  if (length(unloglist) != length(side)) {
    stop("Length of unlog vector mismatches number of axes!")
  }
  if (length(labelslist) != length(side)) {
    stop("Length of labels vector mismatches number of axes!")
  }
  if (length(crunchlist) != length(side)) {
    stop("Length of crunch vector mismatches number of axes!")
  }
  if (length(logprettylist) != length(side)) {
    stop("Length of logpretty vector mismatches number of axes!")
  }
  if (length(prettybaselist) != length(side)) {
    stop("Length of prettybase vector mismatches number of axes!")
  }
  currentfamily = par("family")
  if (hersh & family == "serif") {
    par(family = "HersheySerif")
  }
  if (hersh & family == "sans") {
    par(family = "HersheySans")
  }
  if (hersh == F & family == "serif") {
    par(family = "serif")
  }
  if (hersh == F & family == "sans") {
    par(family = "sans")
  }
  if (usepar) {
    tcl = par()$tcl
    mgp = par()$mgp
  }
  for (i in 1:length(side)) {
    currentside = side[i]
    majorn = majornlist[i]
    minorn = minornlist[i]
    unlog = unloglist[i]
    labels = labelslist[i]
    crunch = crunchlist[i]
    logpretty = logprettylist[i]
    prettybase = prettybaselist[i]
    lims = par("usr")
    if (currentside %in% c(1, 3)) {
      lims = lims[1:2]
      if (par("xlog")) {
        logged = T
      }
      else {
        logged = F
      }
    }
    else {
      lims = lims[3:4]
      if (par("ylog")) {
        logged = T
      }
      else {
        logged = F
      }
    }
    lims = sort(lims)
    if (unlog == "Auto") {
      if (logged) {
        unlog = T
      }
      else {
        unlog = F
      }
    }
    if (logged | unlog) {
      usemultloc = (10^lims[2])/(10^lims[1]) < 50
    }
    else {
      usemultloc = F
    }
    if (unlog) {
      sci.tick = maglab(10^lims, n = majorn, log = T, 
        exptext = T, crunch = crunch, logpretty = logpretty, 
        usemultloc = usemultloc, prettybase = prettybase, 
        hersh = hersh)
      major.ticks = log10(sci.tick$tickat)
      uselabels = sci.tick$exp
      labloc = log10(sci.tick$labat)
      if (usemultloc == F) {
        minors = log10(pretty(10^major.ticks[1:2], minorn + 
          2)) - major.ticks[1]
      }
    }
    if (logged & unlog == F) {
      sci.tick = maglab(10^lims, n = majorn, log = T, 
        exptext = F, crunch = crunch, logpretty = logpretty, 
        usemultloc = usemultloc, prettybase = prettybase, 
        hersh = hersh)
      major.ticks = log10(sci.tick$tickat)
      uselabels = sci.tick$exp
      labloc = log10(sci.tick$labat)
      if (usemultloc == F) {
        minors = log10(pretty(10^major.ticks[1:2], minorn + 
          2)) - major.ticks[1]
      }
    }
    if (logged == F & unlog == F) {
      sci.tick = maglab(lims, n = majorn, log = F, exptext = F, 
        prettybase = prettybase, hersh = hersh)
      major.ticks = sci.tick$tickat
      uselabels = sci.tick$exp
      labloc = sci.tick$labat
      minors = pretty(major.ticks[1:2], minorn + 2) - 
        major.ticks[1]
    }
    if (logged) {
      axis(side = currentside, at = 10^major.ticks, tcl = tcl, 
        labels = FALSE, mgp = mgp, ...)
    }
    else axis(side = currentside, at = major.ticks, tcl = tcl, 
      labels = FALSE, mgp = mgp, ...)
    if (labels) {
      if (logged) {
        axis(side = currentside, at = 10^labloc, tick = F, 
          labels = uselabels, mgp = mgp, ...)
      }
      else axis(side = currentside, at = labloc, tick = F, 
        labels = uselabels, mgp = mgp, ...)
    }
    if (usemultloc == F) {
      minors = minors[-c(1, length(minors))]
      minor.ticks = c(outer(minors, major.ticks, `+`))
      if (logged) {
        axis(currentside, at = 10^minor.ticks, tcl = tcl * 
          ratio, labels = FALSE, ...)
      }
      else axis(currentside, at = minor.ticks, tcl = tcl * 
        ratio, labels = FALSE, ...)
    }
    if (is.null(xlab) == F & currentside == 1) {
      mtext(xlab, 1, line = mtline)
    }
    if (is.null(ylab) == F & currentside == 2) {
      mtext(ylab, 2, line = mtline)
    }
  }
  if (frame.plot) {
    box()
  }
  par(family = currentfamily)
}

您可以尝试修改代码以使用 base 和 log 参数而不是 log10() 但这可能会变得混乱，特别是如果 magicaxis 的各个部分相互调用。

没有魔法轴：

x <- 1:10
y <- 1:10
base <- 2
plot(x,y,axes=FALSE)
axis(1,at=x,labels = base^(x))
axis(2,at=y)