---
title: Inline output
---

We know that $\pi = `{r} pi`$, and the first 3 letters are `{r} LETTERS[1:3]`. The first 3 variables of `mtcars` are `{r} xfun::join_words(names(mtcars)[1:3])`. You will not see this value `{r, eval = FALSE} 2 * pi`.

Some numbers:

```{r}
x = 1.23456789 * 10^c(0, 5, 6, 9, -6) * c(1, 1, -1, 1, 1)
sprintf('%f', x)
```

| n = signif/p = power | n = 3, p = 6 | n = 5/2/4/1/7 | p = 0/4/Inf/9/5 |
|-----------|-----------:|---------------------:|----------------------:|
| x_1       | `{r} x[1]` | `{r, signif=5} x[1]` | `{r, power=0}   x[1]` | 
| x_2 10^5  | `{r} x[2]` | `{r, signif=2} x[2]` | `{r, power=4}   x[2]` |
| x_3 10^6  | `{r} x[3]` | `{r, signif=4} x[3]` | `{r, power=Inf} x[3]` |
| x_4 10^9  | `{r} x[4]` | `{r, signif=1} x[4]` | `{r, power=9}   x[4]` |
| x_5 10^-6 | `{r} x[5]` | `{r, signif=7} x[5]` | `{r, power=5}   x[5]` |

An equation: $Y = 300 `{r, dollar = FALSE, signif = 1} x[3]`x$.
