Update basic-reactivity.Rmd (#500)

basic-reactivity.Rmd

@@ -79,7 +79,7 @@ If you attempt to modify an input inside the server function, you'll get an erro
 
 ```{r, eval = FALSE}
 server <- function(input, output, session) {
-  input$count <- 10  
+  input$count <- 10
 }
 
 shinyApp(ui, server)
@@ -307,7 +307,7 @@ Hopefully, the shapes will help you remember how the components fit together.
 
 ### Execution order
 
-It's important to understand that the order your code runs is solely determined by the reactive graph.
+It's important to understand that the order in which your code runs is solely determined by the reactive graph.
 This is different from most R code where the execution order is determined by the order of lines.
 For example, we could flip the order of the two lines in our simple server function:
 
@@ -375,7 +375,7 @@ This concept is very important and different to most other R code, so I'll say i
     server3 <- function(input, output, session) {
       d <- reactive(c() ^ input$d)
       a <- reactive(input$a * 10)
-      c <- reactive(b() / input$c) 
+      c <- reactive(b() / input$c)
       b <- reactive(a() + input$b)
     }
     ```
@@ -434,7 +434,7 @@ freqpoly <- function(x1, x2, binwidth = 0.1, xlim = c(-3, 3)) {
 
 t_test <- function(x1, x2) {
   test <- t.test(x1, x2)
-  
+
   # use sprintf() to format t.test() results compactly
   sprintf(
     "p value: %0.3f\n[%0.2f, %0.2f]",
@@ -473,13 +473,13 @@ The second row has a wide column for the plot, and a narrow column for the hypot
 ```{r}
 ui <- fluidPage(
   fluidRow(
-    column(4, 
+    column(4,
       "Distribution 1",
       numericInput("n1", label = "n", value = 1000, min = 1),
       numericInput("mean1", label = "µ", value = 0, step = 0.1),
       numericInput("sd1", label = "σ", value = 0.5, min = 0.1, step = 0.1)
     ),
-    column(4, 
+    column(4,
       "Distribution 2",
       numericInput("n2", label = "n", value = 1000, min = 1),
       numericInput("mean2", label = "µ", value = 0, step = 0.1),
@@ -505,14 +505,14 @@ server <- function(input, output, session) {
   output$hist <- renderPlot({
     x1 <- rnorm(input$n1, input$mean1, input$sd1)
     x2 <- rnorm(input$n2, input$mean2, input$sd2)
-    
+
     freqpoly(x1, x2, binwidth = input$binwidth, xlim = input$range)
   }, res = 96)
 
   output$ttest <- renderText({
     x1 <- rnorm(input$n1, input$mean1, input$sd1)
     x2 <- rnorm(input$n2, input$mean2, input$sd2)
-    
+
     t_test(x1, x2)
   })
 }
@@ -638,7 +638,7 @@ Even if you didn't get that error, you'd still have a problem: `x1` and `x2` wou
 If you try to use a function, the app will work:
 
 ```{r}
-server <- function(input, output, session) { 
+server <- function(input, output, session) {
   x1 <- function() rnorm(input$n1, input$mean1, input$sd1)
   x2 <- function() rnorm(input$n2, input$mean2, input$sd2)
 
@@ -672,7 +672,7 @@ This yields a smaller UI object and server function:
 ```{r}
 ui <- fluidPage(
   fluidRow(
-    column(3, 
+    column(3,
       numericInput("lambda1", label = "lambda1", value = 3),
       numericInput("lambda2", label = "lambda2", value = 5),
       numericInput("n", label = "n", value = 1e4, min = 0)
@@ -718,7 +718,7 @@ This change yields the reactive graph shown in Figure \@ref(fig:sim-timer)
 ```{r}
 server <- function(input, output, session) {
   timer <- reactiveTimer(500)
-  
+
   x1 <- reactive({
     timer()
     rpois(input$n, input$lambda1)
@@ -727,7 +727,7 @@ server <- function(input, output, session) {
     timer()
     rpois(input$n, input$lambda2)
   })
-  
+
   output$hist <- renderPlot({
     freqpoly(x1(), x2(), binwidth = 1, xlim = c(0, 40))
   }, res = 96)
@@ -755,7 +755,7 @@ This is a great use case for an `actionButton()`:
 ```{r}
 ui <- fluidPage(
   fluidRow(
-    column(3, 
+    column(3,
       numericInput("lambda1", label = "lambda1", value = 3),
       numericInput("lambda2", label = "lambda2", value = 5),
       numericInput("n", label = "n", value = 1e4, min = 0),
@@ -852,7 +852,7 @@ ui <- fluidPage(
 
 server <- function(input, output, session) {
   string <- reactive(paste0("Hello ", input$name, "!"))
-  
+
   output$greeting <- renderText(string())
   observeEvent(input$name, {
     message("Greeting performed")