Blog moved: blogdown loves Hugo

I’ve (finally) started using blogdown: http://riinu.netlify.com

I will convert all WordPress posts and move them into blogdown shortly…

 

 

Your first Shiny app

What is Shiny?

Shiny is an R package (install.packages("shiny")) for making your outputs interactive. Furthermore, Shiny creates web apps meaning your work can be shared online with people who don’t use R. In other words: with Shiny, R people can make websites without ever learning Javascript etc.

I am completely obsessed with Shiny and these days I end up presenting most of my work in a Shiny app.

If it’s not worth putting in a Shiny app it’s not worth doing.

Your first Shiny app

Getting started with Shiny is actually a lot easier than a lot of people make it out to be. So I created a very short (9 slides) presentation outlining my 5-step programme for your first Shiny app.

This is the app: https://riinu.shinyapps.io/shiny_testing/

This is the presentation: http://rpubs.com/riinu/shiny

And here are the steps (also included in the presentation):

STEP 0: install.packages("shiny"). Use RStudio.

STEP 1: Create a script called app.R using this skeleton:

	library(shiny)
	library(tidyverse)
	library(gapminder)
	# User Interface
	ui <- basicPage(
	plotOutput(outputId = "myplot")
	)
	# Server
	server <- function(input, output) {
	output$myplot <- renderPlot({
	#your plot code here:
	})
	}
	shinyApp(ui, server)

view raw
shiny_skeleton.R
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STEP 2: Copy your plot code into the renderPlot function.

STEP 3: Add a sliderInput to your User Interface (ui). A slider is just one of the many Shiny widgets you could be using: https://shiny.rstudio.com/gallery/widget-gallery.html

STEP 4: Tell your Server you wish the dplyr::filter() to use the value from the slider. All inputs from the User Interface (ui) are stored in input$variable_name: replace the 2007 with input$year.

STEP 5 (optional): Add animate = TRUE.

Press Control+Shift+Enter or the “Run App” button. You now have a Shiny app running on your computer. To deploy it to the internet, e.g. like I’ve done in the link above, see this.

 

R: Replacing NAs in all factors with ‘Missing’

With a simple combination of mutate_if and fct_explicit_na, you can replace all NAs in all factors with “Missing”:

If some of the words/symbols appear in white font, see the example here: Gist: factor_NA_levels.R

library(dplyr)   # gives mutate_if
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
library(forcats) # gives fct_explicit_na

#example dataframe, a and c are factors,
#b is numeric, d is boolean (TRUE/FALSE)
mydata = data.frame(
  a = c( 'Yes', 'No',  NA),
  b = c(  0.5,   NA,   0.6),
  c = c( 'No',   NA,  'Yes'),
  d = c( TRUE,   NA,   FALSE)
)

# Making the missing fields in the columns which are factors explicit
#(by default, fct_explicit_na changes NAs "(Missing)"):
newdata1 = mydata %>% 
  mutate_if(is.factor, fct_explicit_na)

# changing the missing label to "Dunno"
#(note how the syntax is a little bit different 
# than when using fct_explicit_na on a single column)
newdata2 = mydata %>% 
  mutate_if(is.factor, fct_explicit_na, na_level = 'Dunno')


# on a single column it would look like:
mydata$a %>% fct_explicit_na(na_level = 'Dunno')
#> [1] Yes   No    Dunno
#> Levels: No Yes Dunno

mydata 
#>      a   b    c     d
#> 1  Yes 0.5   No  TRUE
#> 2   No  NA <NA>    NA
#> 3 <NA> 0.6  Yes FALSE
newdata1
#>           a   b         c     d
#> 1       Yes 0.5        No  TRUE
#> 2        No  NA (Missing)    NA
#> 3 (Missing) 0.6       Yes FALSE
newdata2
#>       a   b     c     d
#> 1   Yes 0.5    No  TRUE
#> 2    No  NA Dunno    NA
#> 3 Dunno 0.6   Yes FALSE

view raw
factor_NA_levels.md
hosted with ❤ by GitHub

dplyr reference: http://dplyr.tidyverse.org/reference/index.html

forcats reference: http://dplyr.tidyverse.org/reference/index.html

http://surgicalinformatics.org/

Handling your .bib file (LaTex bibliography)

To create a .bib file that only includes the citations you used in the manuscript:

bibexport -o extracted_file.bib manuscript.aux

There are a few issues with this though. The command bibexport comes with the installation of TexLive, but my Windows computer (bless) does not cooperate (“bibexport is not recognised as an internal or external command…”) . So I can only use it on my Mac (luv ya).

 

Get data from ggplot()

ggplot includes built in and seamless functionality that summarises your data before plotting it. As shown in the example below, ggplot_build() can be used to access the summarised dataset.

	library(ggplot2)
	p = ggplot(diamonds, aes(x = color, fill=cut(price,
	breaks = quantile(price),
	include.lowest=TRUE,
	labels = c('Expensive',
	'More expensive',
	'Very expensive',
	'Ridiculously expensive')))) +
	geom_bar(position='fill') +
	facet_wrap(~cut) +
	scale_fill_brewer('Price', palette='OrRd') +
	theme(legend.position='top')
	p
	p_build = ggplot_build(p)
	plot_data = as.data.frame(p_build$data)
	head(plot_data)

view raw
get_ggplot_data.R
hosted with ❤ by GitHub

fill         y count prop x PANEL group    ...
#D7301F 0.2147239    35    1 1     1     4 ...
#FC8D59 0.6871166    77    1 1     1     3 ...
#FDCC8A 0.9570552    44    1 1     1     2 ...
#FEF0D9 1.0000000     7    1 1     1     1 ...
#D7301F 0.1696429    38    1 2     1     8 ...
#FC8D59 0.6116071    99    1 2     1     7 ...
...

HealthyR – a new 2.5 day quick-start R course

 

http://healthyr.surgicalinformatics.org/

R lingua: library vs package