formattable as an htmlwidget

痛定思痛。 2022-09-21 13:09 3阅读 0赞

#### Kent Russell ####

#### 2015-06-12 ####

`formattable` was originally designed to offer additional formatting to the `markdown`generated by the deliberately sparse `knitr::kable`. This design limited `formattable` to only the context of an `Rmarkdown` document. Other contexts, such as the R console or RStudio IDE, would only see the much less attractive `character` markdown output.

library(formattable)
    
    as.character(formattable(head(mtcars,3)))

## [1] "|              |  mpg| cyl| disp|  hp| drat|    wt|  qsec| vs| am| gear| carb|"
    ## [2] "|:-------------|----:|---:|----:|---:|----:|-----:|-----:|--:|--:|----:|----:|"
    ## [3] "|Mazda RX4     | 21.0|   6|  160| 110| 3.90| 2.620| 16.46|  0|  1|    4|    4|"
    ## [4] "|Mazda RX4 Wag | 21.0|   6|  160| 110| 3.90| 2.875| 17.02|  0|  1|    4|    4|"
    ## [5] "|Datsun 710    | 22.8|   4|  108|  93| 3.85| 2.320| 18.61|  1|  1|    4|    1|"

Fortunately, a new function `as.htmlwidget` uses [`markdown`][markdown] to easily convert a`formattable` object to an `htmlwidget`. Once converted to an `htmlwidget`, a user in these other contexts can leverage the infrastructure of [`htmlwidgets`][htmlwidgets] to benefit from the final`HTML` output of `formattable`.

## Demonstration of conversion ##

note, please run these in an `?interactive` environment such as the console or RStudio IDE to see the difference

Let’s explicitly convert a `formattable` to an `htmlwidget` to help us understand what is happening.

as.htmlwidget( formattable( head(mtcars,3) ) )

<table style="border-spacing:0px; border-collapse:collapse; margin:1em auto 20px; border-width:1px; border-color:rgb(221,221,221); border-style:outset none; width:538px; max-width:100%; background-color:transparent"> 
 <thead style="background-color:rgb(247,247,247)"> 
  <tr style=""> 
   <th style="padding:5px; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> &nbsp;</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> mpg</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> cyl</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> disp</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> hp</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> drat</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> wt</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> qsec</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> vs</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> am</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> gear</th> 
   <th style="padding:5px; text-align:right; border-width:0px 2px 2px; border-right-style:none; border-bottom-style:solid; border-left-style:none; line-height:1.42857; vertical-align:bottom; border-bottom-color:rgb(221,221,221)"> carb</th> 
  </tr> 
 </thead> 
 <tbody style=""> 
  <tr style=""> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; vertical-align:top; border-top-color:rgb(221,221,221)"> Mazda RX4</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 21.0</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 6</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 160</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 110</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 3.90</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 2.620</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 16.46</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 0</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 1</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 4</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 4</td> 
  </tr> 
  <tr style=""> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; vertical-align:top; border-top-color:rgb(221,221,221)"> Mazda RX4 Wag</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 21.0</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 6</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 160</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 110</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 3.90</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 2.875</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 17.02</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 0</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 1</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 4</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 4</td> 
  </tr> 
  <tr style=""> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; vertical-align:top; border-top-color:rgb(221,221,221)"> Datsun 710</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 22.8</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 4</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 108</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 93</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 3.85</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 2.320</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 18.61</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 1</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 1</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 4</td> 
   <td style="padding:5px; border-width:1px; border-style:solid none inset; line-height:1.42857; text-align:right; vertical-align:top; border-top-color:rgb(221,221,221)"> 1</td> 
  </tr> 
 </tbody> 
</table>

Although our `htmlwidget` version looks virtually the same when generated from a `Rmd`document such as this vignette, a user in the console will have a noticeably different experience than before. The function `interactive()` can help `formattable` to guess when it should automatically convert to a `htmlwidget`. `formattable` will not auto-convert in the special situation where `format = "pandoc"` as shown below.

formattable( head(mtcars,3), format = "pandoc" )

## 
    ## 
    ##                   mpg   cyl   disp    hp   drat      wt    qsec   vs   am   gear   carb
    ## --------------  -----  ----  -----  ----  -----  ------  ------  ---  ---  -----  -----
    ## Mazda RX4        21.0     6    160   110   3.90   2.620   16.46    0    1      4      4
    ## Mazda RX4 Wag    21.0     6    160   110   3.90   2.875   17.02    0    1      4      4
    ## Datsun 710       22.8     4    108    93   3.85   2.320   18.61    1    1      4      1

If you prefer to avoid the automatic conversion to an `htmlwidget`, use`as.character(formattable(...))`.

As an additional example, we can recreate [the example][] from [Tristan Mahr(@tjmahr)][Tristan Mahr_tjmahr]with `formattable`.

## use formattable to recreate the example in
    ## https://rpubs.com/tjmahr/prettytables_2015
    
    library("magrittr")
    library("dplyr")

## Warning: package 'dplyr' was built under R version 3.1.3

library("broom")
    library("stringr")
    library("knitr")
    
    fix_names <- . %>%
     str_replace(".Intercept.", "Intercept") %>%
     str_replace("Species", "") %>%
     # Capitalize species names
     str_replace("setosa", "Setosa") %>%
     str_replace("versicolor", "Versicolor") %>%
     str_replace("virginica", "Virginica") %>%
     # Clean up special characters
     str_replace_all(".Width", " Width") %>%
     str_replace_all(".Length", " Length") %>%
     str_replace_all(":", " x ")
    
    # Print with n digits of precision
    fixed_digits <- function(xs, n = 2) {
      formatC(xs, digits = n, format = "f")
    }
    
    # Don't print leading zero on bounded numbers.
    remove_leading_zero <- function(xs) {
      # Problem if any value is greater than 1.0
      digit_matters <- xs %>% as.numeric %>%
     abs %>% is_greater_than(1)
      if (any(digit_matters)) {
        warning("Non-zero leading digit")
      }
      str_replace(xs, "^(-?)0", "\\1")
    }
    
    lm(Sepal.Length ~ Species * Sepal.Width, iris) %>%
     tidy %>%
     set_colnames( c("Param", "Estimate", "SE", "_t_", "_p_") ) %>%
     mutate( Param = fix_names( Param ) ) %>%
     formattable(
        list(
          "_p_" = formatter(
            "span"
            ,style = x ~ ifelse( x < 0.05, style( color = "red", font.weight = "bold" ), NA )
            ,ps ~ {
              tiny <- "< .001"
              ps_chr <- ps %>% fixed_digits(3) %>%
     remove_leading_zero
              ps_chr[ps < 0.001] <- tiny
              ps_chr
            }
          )
        )
        ,digits=2
      )

<table style="border-spacing:0px; border-collapse:collapse; margin:1em auto; border-width:1px; border-color:rgb(221,221,221); border-style:outset none; background-color:transparent"> 
 <thead style="background-color:rgb(247,247,247)"> 
  <tr style=""> 
   <th align="right" style="padding:5px; border-width:2px; border-style:inset none"> Param</th> 
   <th align="right" style="padding:5px; border-width:2px; border-style:inset none"> Estimate</th> 
   <th align="right" style="padding:5px; border-width:2px; border-style:inset none"> SE</th> 
   <th align="right" style="padding:5px; border-width:2px; border-style:inset none"> <span style="">t</span></th> 
   <th align="right" style="padding:5px; border-width:2px; border-style:inset none"> <span style="">p</span></th> 
  </tr> 
 </thead> 
 <tbody style=""> 
  <tr style=""> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> Intercept</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 2.64</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.57</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 4.62</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> <span style="color:red"><strong>&lt; .001</strong></span></td> 
  </tr> 
  <tr style="background-color:rgb(247,247,247)"> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> Versicolor</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.90</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.80</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 1.13</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> <span style="">.261</span></td> 
  </tr> 
  <tr style=""> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> Virginica</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 1.27</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.82</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 1.55</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> <span style="">.123</span></td> 
  </tr> 
  <tr style="background-color:rgb(247,247,247)"> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> Sepal Width</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.69</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.17</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 4.17</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> <span style="color:red"><strong>&lt; .001</strong></span></td> 
  </tr> 
  <tr style=""> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> Versicolor x Sepal Width</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.17</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.26</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.67</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> <span style="">.503</span></td> 
  </tr> 
  <tr style="background-color:rgb(247,247,247)"> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> Virginica x Sepal Width</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.21</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.26</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> 0.83</td> 
   <td align="right" style="padding:5px; border-width:1px; border-style:inset none; line-height:18px"> <span style="">.411</span></td> 
  </tr> 
 </tbody> 
</table>

## htmlwidgets inside a formattable ##

Courtesy of this [issue][] we have an interesting example of interactive [`sparkline`][sparkline]`htmlwidgets` inside a `formattable`. \*\* note: only works in Rmd currently \*\*

# use builtin chickwts ?chickwts
    
    library(dplyr)
    library(formattable)
    # devtools::install_github( "htmlwidgets/sparkline" )
    library(sparkline)
    
    chickwts %>%
     group_by( feed ) %>%
     summarise(
        weight = sprintf("`r sparkline(c(%s), type = 'box')`", paste0(weight, collapse=","))
      ) %>%
     ungroup %>%
     as.data.frame %>%
     formattable(
        list(
          weight = function(spkline){
            sapply(spkline, function(md) knitr::knit(text=md, quiet=T) )
          }
        )
      )

[markdown]: http://cran.r-project.org/web/packages/markdown/index.html
[htmlwidgets]: http://htmlwidgets.org/
[the example]: https://rpubs.com/tjmahr/prettytables_2015
[Tristan Mahr_tjmahr]: https://github.com/tjmahr
[issue]: https://github.com/renkun-ken/formattable/issues/10
[sparkline]: https://github.com/htmlwidgets/sparkline