[英]Replace a numerical value by NA based on conditions from other columns
这与之前的问题有关,可以在以下网址找到:
以下是数据:
DT <- data.table(a = sample(c("C","M","Y","K"), 100, rep=TRUE),
b = sample(c("A","S"), 100, rep=TRUE),
f = round(rnorm(n=100, mean=.90, sd=.08),digits = 2) ); DT
我希望对以下功能进行优雅而简洁的重写:
`%between%` <- function(x, vals) { x >= vals[1] & x <= vals[2]}
`%nbetween%` <- Negate(`%between%`)
和以下脚本用NA替换满足某些条件的某些值
DT[a == "C" & b %in% c("A", "S") & f %nbetween% c(.85, .95), f := NA]
DT[a == "M" & b %in% c("A", "S") & f %nbetween% c(.85, .95), f := NA]
DT[a == "Y" & b %in% c("A", "S") & f %nbetween% c(.80, .90), f := NA]
DT[a == "K" & b %in% c("A", "S") & f %nbetween% c(.95, 1.10), f := NA]
如果你矢量化你的功能,那么你可以使它更优雅:
`%between%` <- function(x, vals, vals2) x >= vals & x <= vals2
`%nbetween%` <- Negate(`%between%`)
# This will get you a nice ranges table.
ranges<-data.table(a=c('C','M','Y','K'),low=c(0.85,0.85,0.80,0.95),high=c(0.95,0.95,0.90,1.10))
# Set the keys for an easy merge.
setkeyv(ranges,'a')
setkeyv(DT,'a')
# Merge and filter.
DT<-merge(DT,ranges,all.x=TRUE)[b %in% c('A','S') & `%nbetween%`(f,low,high),f:=NA ]
# A nice suggestion from the comments:
DT<-DT[ranges][b %in% c('A','S') & `%nbetween%`(f,low,high),f:=NA]
# a b f low high
# 1: C S 0.88 0.85 0.95
# 2: C S NA 0.85 0.95
# 3: C S 0.92 0.85 0.95
# 4: C A 0.94 0.85 0.95
# 5: C S NA 0.85 0.95
# 6: C S 0.90 0.85 0.95
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