最大值或最小值，取决于另一个变量 [英] Max or min depending on another variable

问题描述

我需要根据波高的方向来计算波高的最大值和最小值，也就是说，我有两个变量:

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(波高)
• 方向(膨胀方向)

我需要知道方向在11.25和33.75度之间的波的最大波高.

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

现在，使用以下功能:

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

但是我不同意结果与现有数据.

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

推荐答案

假定您的数据框名为df，变量名为Hs和Direction，则可以使用

Assume your dataframe is called df, your variables are called Hs and Direction, you can use

max(df$Hs[df$Direction >= 11.25 & df$Direction <= 33.75])

以获得在Direction的定义值范围内的所有Hs值中的最大值.

to get the maximum of all Hs values within the defined value range of Direction.

如果您像我一样不喜欢分别定义间隔的上限和下限，则可以使用此整齐的函数(我发现

If you, like me, dislike the necessity to define both lower and upper bounds of the interval separately, you can use this neat function (which I found here):

in_interval <- function(x, interval){
   stopifnot(length(interval) == 2L)
   interval[1] < x & x < interval[2]
}

然后使用

max(df$Hs[in_interval(df$Direction, c(11.25, 33.75))])

这篇关于最大值或最小值，取决于另一个变量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！