Monse Aleman -3 years ago 99
R Question

# Max or min depending on another variable

I need to calculate the max and min of the wave height according to the direction from which it comes, that is to say, I have two variables:

• Hs (wave height)

• Direction (direction of the swell)

And I need to know the maximum wave height for waves with a direction between 11.25 and 33.75 degrees.

For now, use the function:

``````Max (Hs [Direction [11.25: 33.75]))
``````

But I do not agree the result with the data that I have.

The answer from @LAP is absolutely correct, but you can also use the `dplyr` package to get both the `max` and `min`.

First let's create some sample data.

``````df <- data.frame(Hs = rnorm(327), Direction = runif(327, 0, 364))
``````

Now let's calculate.

``````library(dplyr)

df %>%
filter(Direction >= 11.25 & Direction <= 33.75) %>%
summarise(max(Hs), min(Hs))
``````
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