Support for svystat/svyby objects

[carlganz]

Hello,

Thanks for the wonderful package. At the moment, svystat and svyby objects from the survey package don't print as expected with pander. The default print method for these objects includes standards errors, and the pander output probably should too.

library(survey)
library(pander)

data(api)

dstrat <- svydesign(id=~1,strata=~stype, weights=~pw, data=apistrat, fpc=~fpc)

x <- svytotal(~sch.wide, dstrat)

class(x)

pander(x)

# ideally would want something like this

pander.svystat <- function(x = NULL, ...) {
  x <- as.data.frame(x)
  pandoc.table(x, ...)

}

pander.svyby <- pander.svystat

# works better now

pander(x)

pander(svyby(~api00,~sch.wide,dstrat,svymean))

It's not that helpful obviously, since the user could always as.data.frame themselves before calling pander, but I feel like the purpose of pander is to make printing objects work as-is.

Thanks

[mbacou]

Same issue and same request here. Right now I use my own dirty hack to collect results from multiple svyby(), svymean(), svyquantile() calls, and then tabular() to pretty format. Would be nice is someone could build a generic method for survey objects.

svyCrossTab <- function(formula, by, design, quantiles=c(.25,.5,.75), labels=NULL) {

  # Pass a list of formulas (list(~var1, ~var2, ...))
  # Then use tables::tabular() to format nested tables

  require(survey)
  require(data.table)
  require(stringr)

  # Reshape means
  x <- lapply(formula, function(x) {
    m <- svyby(x, by, design, svymean, na.rm=TRUE)
    m <- as.data.table(ftable(m))
    return(m)
  })
  x <- rbindlist(x)
  setnames(x, c("by", "stat", "var", "Mean"))
  x[stat=="svymean", stat := "est."]
  x[stat=="SE", stat := "std. err."]

  # Reshape quantiles
  y <- lapply(formula, function(x) {
    m <- svyby(x, by, design, svyquantile, quantiles, ci=TRUE, na.rm=TRUE)
    m <- as.data.table(ftable(m))
    m[, var := as.character(x)[2]]
    return(m)
  })
  y <- rbindlist(y)  
  setnames(y, c("by", "stat", "qtl", "value", "var"))
  y[stat=="svyquantile", stat := "est."]
  y[stat=="SE", stat := "std. err."]
  y[, qtl := paste0("Q", as.numeric(as.character(qtl))*100)]
  y <- dcast(var+by+stat~qtl, data=y)

  setkey(x, var, by, stat)
  setkey(y, var, by, stat)
  x <- x[y]

  # Add optional labels
  if(!missing(labels)) for (i in seq_along(var)) x[var==as.character(formula[[i]])[2],
    var := labels[i]]

  x[, var := factor(str_replace(var, fixed("I("), fixed("(")), ordered=T)]
  x[, stat := factor(as.character(stat), ordered=T)]
  setcolorder(x, c(3,1,2,4:ncol(x)))
  setnames(x, 1:3, c("Variable", "By", "Stat"))
  return(x)
}

# Then a little tabular() magic
pander(tabular(
  Variable*(Mean+Q25+Q50+Q75)~Heading()*By*Heading()*Stat*Heading()*Justify(c,r)*Format(digits=0, big.mark=",", nsmall=2)*identity,
  data=dt),
  emphasize.italics.cols=c(4,6,8), split.table=Inf,
  caption="Tab. My Caption")

------------------------------------------------------------------------------------------
        \             \      SSHF\           \    TSHF\           \     CSHF\           \ 
     Variable                  est.   std. err.     est.   std. err.      est.   std. err.
------------------- ------ -------- ----------- -------- ----------- --------- -----------
  (aggross/1000)     Mean    26,344     *1,452*   27,179     *1,120*       514        *95*
                     Q25        139       *699*    8,187       *878*        44         *6*
                     Q50     18,266     *2,255*   20,195     *1,273*       145        *29*
                     Q75     41,643     *3,258*   38,530     *1,997*       417        *59*
  (agsales/1000)     Mean       349       *158*      313        *28*       477        *95*
                     Q25          0         *0*       16         *1*        35         *5*
                     Q50          0         *0*       57         *5*       108        *18*
                     Q75         33         *8*      180        *20*       331        *60*
------------------------------------------------------------------------------------------
Table: Tab. My Caption