Demo: Read-Only Code Cells

Overview

This demo shows how a code cell can be placed into a read-only mode.

read-only Option

The read-only option modifies the interactive context such that changes to the cell’s code is not possible.

For example, try modifying the value associated with age in the following cell.

```{webr-r}
#| context: interactive
#| read-only: true
# Try modifying age
age <- 42
cat("Your age is: ", age, fill = TRUE)
```

Constraining Modifications

We can pair read-only with autorun to create a constrained example allowing us to focus on a single piece of the code.

For example, let’s say we want to understand what happens when we increase the number of observations randomly sampled from a normal distribution. We could define two interactive cells:

  1. one cell exposing changes to the number of samples, e.g. n; and,
  2. a second cell containing graphing code that is restricted from being modified.

Try different values for n by modifying the assignment statement.

Then, press “Run Code” to recreate the graph and see how the distribution changed:

```{webr-r}
#| context: interactive
#| autorun: true
# Experiment with different sample sizes by
# changing the n value and re-running the code
# cell.
n <- 100
```
```{webr-r}
#| context: interactive
#| autorun: true
#| read-only: true
samples = rnorm(n)
hist(samples,
  main = "Randomly Sampled Normal Distribution",
  sub = paste("Based on", n, "samples"),
  xlab = "Sample Value"
)
```

Fin

In this demo, we saw the possibility of preventing modifications to a code cell area.