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shinyServer(function(input, output) { |
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#This function is repsonsible for loading in the selected file |
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filedata <- reactive({ |
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infile <- input$datafile |
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if (is.null(infile)) { |
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# User has not uploaded a file yet |
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return(NULL) |
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} |
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read.csv(infile$datapath) |
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}) |
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#The following set of functions populate the column selectors |
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output$toCol <- renderUI({ |
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df <-filedata() |
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if (is.null(df)) return(NULL) |
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items=names(df) |
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names(items)=items |
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selectInput("to", "To:",items) |
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}) |
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output$fromCol <- renderUI({ |
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df <-filedata() |
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if (is.null(df)) return(NULL) |
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items=names(df) |
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names(items)=items |
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selectInput("from", "From:",items) |
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}) |
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#The checkbox selector is used to determine whether we want an optional column |
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output$amountflag <- renderUI({ |
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df <-filedata() |
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if (is.null(df)) return(NULL) |
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checkboxInput("amountflag", "Use values?", FALSE) |
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}) |
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#If we do want the optional column, this is where it gets created |
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output$amountCol <- renderUI({ |
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df <-filedata() |
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if (is.null(df)) return(NULL) |
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#Let's only show numeric columns |
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nums <- sapply(df, is.numeric) |
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items=names(nums[nums]) |
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names(items)=items |
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selectInput("amount", "Amount:",items) |
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}) |
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#This previews the CSV data file |
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output$filetable <- renderTable({ |
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filedata() |
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}) |
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#This function is the one that is triggered when the action button is pressed |
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#The function is a geocoder from the ggmap package that uses Google maps geocoder to geocode selected locations |
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geodata <- reactive({ |
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if (input$getgeo == 0) return(NULL) |
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df=filedata() |
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if (is.null(df)) return(NULL) |
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#The function acts reactively when one of the variables it uses is changed |
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#If we don't want to trigger when particular variables change, we need to isolate them |
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isolate({ |
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#Get the CSV file data |
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dummy=filedata() |
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#Which from/to columns did the user select? |
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fr=input$from |
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to=input$to |
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#If locations are duplicated in from/to columns, dedupe so we don't geocode same location more than once |
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locs=data.frame(place=unique(c(as.vector(dummy[[fr]]),as.vector(dummy[[to]]))),stringsAsFactors=F) |
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#Run the geocoder against each location, then transpose and bind the results into a dataframe |
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cbind(locs, t(sapply(locs$place,geocode, USE.NAMES=F))) |
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}) |
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}) |
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#This reactive function is essentially chained on the previous one |
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geodata2 <- reactive({ |
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if (input$getgeo == 0) return(NULL) |
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df=filedata() |
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if (input$amountflag != 0) { |
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maxval=max(df[input$amount],na.rm=T) |
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minval=min(df[input$amount],na.rm=T) |
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df$b8g43bds=10*df[input$amount]/maxval |
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} |
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gf=geodata() |
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df=merge(df,gf,by.x=input$from,by.y='place') |
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merge(df,gf,by.x=input$to,by.y='place') |
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}) |
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output$geotable <- renderTable({ |
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if (input$getgeo == 0) return(NULL) |
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geodata2() |
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}) |
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}) |
