Downsample

## Usage

```
resample_down(x, y, ...)
# S4 method for class 'numeric,numeric'
resample_down(x, y, by)
# S4 method for class 'ANY,missing'
resample_down(x, y, by)
```

## Arguments

- x, y
A

`numeric`

vector. If`y`

is missing, an attempt is made to interpret`x`

in a suitable way (see`grDevices::xy.coords()`

).- ...
Currently not used.

- by
An

`integer`

specifying the downsampling factor.

## Value

Returns a `list`

with two components `x`

and `y`

.

## See also

Other resampling methods:
`resample_bin()`

,
`resample_interpolate()`

## Examples

```
## X-ray diffraction
data("XRD")
## Plot spectrum
plot(XRD, type = "l", xlab = expression(2*theta), ylab = "Count")
## Bin by 3
XRD_bin_mean <- resample_bin(XRD, by = 3, f = mean)
XRD_bin_min <- resample_bin(XRD, by = 3, f = min)
plot(XRD, type = "l", xlim = c(25, 35),
xlab = expression(2*theta), ylab = "Count")
lines(XRD_bin_mean, type = "l", col = "red")
lines(XRD_bin_min, type = "l", col = "green")
## Downsample by 10
XRD_down <- resample_down(XRD, by = 10)
plot(XRD, type = "l", xlim = c(20, 40),
xlab = expression(2*theta), ylab = "Count")
lines(XRD_down, type = "l", col = "red")
## Linearly interpolate
XRD_approx <- resample_interpolate(XRD, from = 20, to = 40, by = 0.02)
plot(XRD, type = "l", xlim = c(20, 40),
xlab = expression(2*theta), ylab = "Count")
lines(XRD_approx, type = "l", col = "red")
```