R中仅查找并显示特定范围的行

我想知道如何根据固定值显示特定范围的行:

y<-c(1,59,60,65,85,86,1550,97)
z<-c(1:8)
test<-cbind(y,z)
test

y z
[1,]    1 1
[2,]   59 2
[3,]   60 3
[4,]   65 4
[5,]   85 5
[6,]   86 6
[7,] 1550 7
[8,]   97 8

那么，碰巧我只需要看到85行中的+/-2行，有没有一种方法可以从表中提取？理想情况下，我希望有这样的东西:

非常感谢你的帮助.

Updated version with new function written by Peter :个

#required libiaries

library(quantmod)
library(pedquant)

# download option chain from yahoo finance, using an example of ticker "BABA" & exp= "2023-06-23"
ticker<-c("BABA")
options<-getOptionChain(ticker,Exp="2023-06-23")

# seperate call/put options and display only Strike, Last Price, Volume
call_option<-options$calls[,c("Strike","Last","Vol")]
put_option<-options$puts[,c("Strike","Last","Vol")]

#getting the updated stock price to filter at-the-money level 

ticker_price<-md_stock(ticker,type="real")
price<-ticker_price$close

view_window <- function(dfr, var, x, pm){
  
  idx <- which(abs(test[, var]-x) == min(abs(test[, var] - x)))
  
  return(dfr[(idx - pm) : (idx + pm), ])
  
}

view_window(dfr=call_option,
            var=call_option$Strike,
            x=price,pm=3)

Error in test[, var] : subscript out of bounds

在本例中，数据帧[dfr]是CALL_OPTION，var是CALL_OPTION$STRING，x是交易价格，但是，显示了错误消息"Error in test[，var]:下标Out Out Bound"，非常确定我的数据帧的格式有问题n函数应该工作得很好.有什么主意吗？非常感谢.