I have these data

```
  Open   High   Low    Close
1 6709.0 6709.5 6703.5 6705.0
2 6705.0 6710.5 6705.0 6710.0
3 6710.5 6713.5 6710.5 6713.5
4 6713.5 6713.5 6711.5 6712.0
5 6712.5 6715.0 6712.5 6714.0
6 6714.0 6716.0 6713.5 6716.0

```

which are `OHLC` prices of `1` minute bars. I want to find `OHLC` of 5 minute bars.
`Open` and `Close` are easy, but I don't know how to do `High` and `Low`.

I need to find the `maximum/minimum` values in a subset of the data.
So first I need to find `max(data[1:5,2])` then `max(data[6:10,2])` and so on. And I need to put the values in a vector called `High`. And for `Low` prices `min(data[1:5,3])`. 

I need something like a `for loop` with two variables.