用R插值数据帧内行数据的干净方法

Question

I have the following dataframe, let's call it DF:

DF <- data.frame(
    x = c(0, 2, 4, 6, 8),
    y = c(1, 2, 3, 4, 5)
)

I would like to know if there is an easy and clean way to end up with the following dataframe, let's call it DF_target from DF:

DF_target <- data.frame(
    x = c(0, 1, 2, 3, 4, 5, 6, 7, 8),
    y = c(1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5)
)

I would like to use linear interpolation between the rows.

So basically something like:

function(DF) -> DF_target

The example has been simplified.

Answer 1

This is what approx was built to do.

approx(DF$x, DF$y, n=9)
$x
[1] 0 1 2 3 4 5 6 7 8

$y
[1] 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

which returns (from ?approx )

a list of linearly interpolated data points.

To make it a data.frame, just wrap the function in data.frame .

data.frame(approx(DF$x, DF$y, n=9))
  x   y
1 0 1.0
2 1 1.5
3 2 2.0
4 3 2.5
5 4 3.0
6 5 3.5
7 6 4.0
8 7 4.5
9 8 5.0