Shiny/R - Unable to rename column headers - r

Question

Hoping for some expertise. the following code snippet does the following:
allows the user to select which variables (columns) they want from a CSV file, then generates numeric input fields for each one.
populates the dataframe with the values entered by the user.
However, Shiny assigns column headers to the data frame, and I've tried everything I could find to change them and nothing seems to work.
Can anyone tell me what I'm doing wrong?
df_sel() - this the function that selected the variables
this is the R.UI Section
ui <- fluidPage(
# App title ----
titlePanel(title = h1("Variable Selection Example", align = "center")),
# Sidebar layout with input and output definitions ----
sidebarLayout(
# Sidebar panel for inputs ----
sidebarPanel(
# Input: Select a file ----
fileInput("uploaded_file", "Choose CSV File",
multiple = TRUE,
accept = c("text/csv",
"text/comma-separated-values,text/plain",
".csv")),
# Horizontal line ---- This allows the user to create a bunch of repeated values for the numerica inputs they later create
sliderInput("months", "Forecast Months:",
min = 0, max = 60,
value = 1),
tags$hr(),
# Input: Checkbox if file has header ----
checkboxInput("header", "Header", TRUE),
# Input: Select separator ----
radioButtons("sep", "Separator",
choices = c(Semicolon = ";",
Comma = ",",
Tab = "\t"),
selected = ","),
# Horizontal line ----
tags$hr(),
# Input: Select number of rows to display ----
radioButtons("disp", "Display",
choices = c(All = "all",
Head = "head"),
selected = "all"),
# Select variables to display ----
uiOutput("checkbox")
),
# Main panel for displaying outputs ----
mainPanel(
uiOutput("input_ui"), #numeric inputs
tableOutput("table1")) #table to display input values
)
)
this is in the R.Server section
server <- function(input, output, session) {
#assign csv file to dataframe df
df <- reactive({
req(input$uploaded_file)
read.csv(input$uploaded_file$datapath,
header = input$header,
sep = input$sep)
})
# Dynamically generate UI input when data is uploaded ----
output$checkbox <- renderUI({
checkboxGroupInput(inputId = "select_var",
label = "Select variables",
choices = setdiff(names(df()), input$select_dev),
selected = setdiff(names(df()), input$select_dev))
})
# Select columns to print ----
df_sel <- reactive({
req(input$select_var)
df_sel <- df() %>% select(input$select_var)
})
output$input_ui <- renderUI({ #this creates dynamic numeric inputs based on the variables selected by the user
pvars <- df_sel()
varn = names(df_sel())
lapply(seq(pvars), function(i) {
numericInput(inputId = paste0("range", pvars[i]),
label = varn,
value = 0)
})
})
numbers <- reactive({ #this creates a reactive dataframe for the numbers
pvars <- df_sel()
num = as.integer(ncol(pvars))
print(num)
pred <- data.frame(lapply(1:num, function(i) {
input[[paste0("range", pvars[i])]]
}))
n = input$months #pull number from that slider up in the UI section
pd = data.frame(pred, i=rep(1:n,ea=NROW(input$months)))
pd[1:(length(pd)-1)]
#colnames(pd, c(df_sel())) #this does not seem to work at all!!!
})
output$table1 <- renderTable({
numbers()
fv = numbers()
print(dim(fv)) #check the dimensions of the table
print(fv) # chcek the table is populating correctly.
#df1 <- fv #show the table
})
}
# Create Shiny app ----
shinyApp(ui = ui, server = server)

Answer 1

I came up with a solution to my own question. If anyone can improve upon it, please let me know. This code goes in the R.Server section.
#This creates sliders from the selected variables from the reactive function called
#"df_sel()". Note the use of "tagList". The RenderUI function below creates as
#many sliders as variables selected, and passes in the correct variable name.
#It selects the last data value from each column, since this is time series data,
#the last data value \ (most recent) was desired.
output$scplan <- renderUI({
vars <- df_sel()
n = nrow(vars)
tagList(lapply(colnames(vars), function(z) {
sliderInput(
sprintf("%s",z),
label = z,
min = ceiling(min(vars[[z]])), # min value is the minimum of the column
max = ceiling(max(vars[[z]])), # max is the max of the column
value = vars[[z]][[n]])
}))
#this reactive function creates a dataframe from variables that were selected from
#checkboxes. The user moves the sliders to generate the values, and the code
#repeats the values for as many "input$months" as were selected.
sp_numbers <- reactive({
vars <- df_sel()
num = as.integer(ncol(vars))
sp_pred <- data.frame(lapply(colnames(vars), function(z) {
input[[z]]
}))
names(sp_pred) <- colnames(vars)
n = input$sp_months
df_sp_pred = data.frame(sp_pred, z=rep(z:n,ea=NROW(input$sp_months)))
df_sp_pred[1:(length(df_sp_pred)-1)] #this removes the last column which just shows the repeat count
})
#this code renders the table of the dataframe created above.
output$spo_table <- renderTable({
sp_numbers()
})