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r - 如何从值的范围中找到给定的值？

问题描述

I have have the below data :

Y          z
100-800    a
150-600    b
200-300    c
400-600    d
4000-12000 e

任何帮助将非常感激。

基于x的给定值（即x = 100），它应该找到Y的给定范围内的值，并给出Y和z的对应值。如果给定的x不在Y的给定范围内，那么它应该找到较近的范围并给出相应的 Y 和 Z 值。

DT[, list(OK = 1 %in% seq(Y, Y)), by = Z]

对于 X=110 的给定值

输出应该是

Y          Z
100-800    a

For x=200

Y          z
100-800    a
150-600    b
200-300    c

For x=12500

Y             z
4000-12000    e

标签： r

解决方案

We can write a helper function using tidyr::separate to separate columns. In case if there are no indices which fall within the range we compare the value with lowest value and highest value in the dataframe and return the row accordingly. 

subset_fun <- function(df, val) {
   df1 <- tidyr::separate(df, Y, c("low", "high"), sep = "-",convert = TRUE)
   inds <- with(df1, val >= low & val <= high)
   if (any(inds))
      df[inds, ]
   else if (min(df1$low) > val) df[which.min(df1$low), ] 
        else df[which.max(df1$high), ] 
}

subset_fun(df, 100)
#        Y z
#1 100-800 a

subset_fun(df, 200)
#        Y z
#1 100-800 a
#2 150-600 b
#3 200-300 c

subset_fun(df, 12500)
#           Y z
#5 4000-12000 e

subset_fun(df, 0)
#        Y z
#1 100-800 a

data

df <- structure(list(Y = structure(1:5, .Label = c("100-800", "150-600", 
"200-300", "400-600", "4000-12000"), class = "factor"), 
z = structure(1:5, .Label = c("a", "b", "c", "d", "e"), class = "factor")), 
class = "data.frame", row.names = c(NA, -5L))

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