Output If statement on R Shiny - r

Question

I am new to R shiny and am trying to make a diet calculator (assuming you have isotope values for 15N and 13C measurements for your fingernail/hair samples). I am having trouble formatting my if statement to produce my output statement that gives you a diet based on the d13C and d15N inputs (i.e., if values d15Nair = 6, d13Cpdb = -24...... "your diet primarily consists of fruit, vegetables, and grain eaters").
It seems to me that this strictly a formatting issue, I would appreciate any feedback.
library(shiny)
library(tidyverse)
ui <- fluidPage(numericInput(inputId = "Cnumber",
label = "d13C (per mil)",
value = "2",),
numericInput(inputId = "Nnumber",
label = "d15N (per mil)",
value = "1"),
textOutput(outputId = "DietCalculator")
)
server <- function(input, output, session) {
d13Cpdb <- reactive(input$Cnumber)
d15Nair <- reactive(input$Nnumber)
}
if(d13Cpdb <= -23 & d13Cpdb >= -29 & d15Nair <= 7 & d15Nair >= -1)
{print("Fruits, Vegetables, and Grain eaters")
} else if(d13Cpdb <= -22 & d13Cpdb >= -29 & d15Nair <= 11 & d15Nair >= -7)
{print("Non-corn-Fed Meat Consumers")
} else if(d13Cpdb <= -17 & d13Cpdb >= -19 & d15Nair <= 6 & d15Nair >= 4)
{print("Dairy Consumers")
} else if(d13Cpdb <= -21 & d13Cpdb >= -18 & d15Nair <= 17 & d15Nair >= 12)
{print("Marine Fish Consumers")
} else if(d13Cpdb <= -12 & d13Cpdb >= -17 & d15Nair <= 11 & d15Nair >= 3)
{print("Corn-Fed Meat Consumers")
} else if(d13Cpdb <= -10 & d13Cpdb >= -13 & d15Nair <= 5 & d15Nair >= 3)
{print("Corn & Sugar Cane Product Consumers, eat healthier")
} else {(print("Diverse diets incorporating more than one source"))
}
output$DietCalculator <- renderText({input$Cnumber})
output$DietCalculator <- renderText({input$Nnumber})
shinyApp(ui = ui, server = server)

Answer 1

As #YBS mentioned, as d13Cpdb is a reactive, you need to change the code to be d13Cpdb(). The second thing I did was move the end bracket of server<-function(input, output, session){ } to encompass the output$DietCalculator. Also noteworthy that you have two different renderText() codes going to the same output$DietCalculator. If you wanted to display both, then you would need to make a second output of a different name, or perhaps if you wanted them both in one output, use a paste function, something like paste0("Cnumber is ", input$Cnumber," and Nnumber is ", input$Nnumber). Lastly, I was thinking you wanted your if statement to display in the renderText(), so I moved that into the renderText(), and removed all of the print() functions. This way it would put it in the shiny app. Hopefully this is about what you were looking for. Best of luck in your future endeavors!
library(shiny)
library(tidyverse)
ui <- fluidPage(numericInput(inputId = "Cnumber",
label = "d13C (per mil)",
value = "2",),
numericInput(inputId = "Nnumber",
label = "d15N (per mil)",
value = "1"),
textOutput(outputId = "DietCalculator")
)
server <- function(input, output, session) {
d13Cpdb <- reactive(input$Cnumber)
d15Nair <- reactive(input$Nnumber)
output$DietCalculator <- renderText({
req(input$Cnumber, input$Nnumber)
if(d13Cpdb() <= -23 & d13Cpdb() >= -29 & d15Nair() <= 7 & d15Nair() >= -1)
{"Fruits, Vegetables, and Grain eaters"
} else if(d13Cpdb() <= -22 & d13Cpdb() >= -29 & d15Nair() <= 11 & d15Nair() >= -7)
{"Non-corn-Fed Meat Consumers"
} else if(d13Cpdb() <= -17 & d13Cpdb() >= -19 & d15Nair() <= 6 & d15Nair() >= 4)
{"Dairy Consumers"
} else if(d13Cpdb() <= -21 & d13Cpdb() >= -18 & d15Nair() <= 17 & d15Nair() >= 12)
{"Marine Fish Consumers"
} else if(d13Cpdb() <= -12 & d13Cpdb() >= -17 & d15Nair() <= 11 & d15Nair() >= 3)
{"Corn-Fed Meat Consumers"
} else if(d13Cpdb() <= -10 & d13Cpdb() >= -13 & d15Nair() <= 5 & d15Nair() >= 3)
{"Corn & Sugar Cane Product Consumers, eat healthier"
} else {"Diverse diets incorporating more than one source"
}
})
}
shinyApp(ui = ui, server = server)