CODEWITHSUNDEEP
rif-statementfilter
Mark Davies
Mark Davies

Reputation: 940

Filtering a table to find a single row in R with an if_else or case_when statement

I need to filter my data to select a single row that is the latest Date. When there are two rows with the latest dates, I then need to filter based on the test result:

If the max(test) >= 60 I want to select the row with the min(test), else I want to select the row with max(test)

library(dplyr)
Date= c("2020/04/16", "2020-07-01", "2020-07-01")
ID= c(12,12,12)
test= rnorm(3, mean=150, sd=60)
data= data.frame(ID, Date, test)
data$Date = lubridate::ymd(data$Date)

I have attempted the following

data = data%>%
  filter(Date == max(Date))%>%
  filter(if_else(max(test) >= 60, test == min(test), test == max(test)))

and

data = data%>%
  filter(Date == max(Date))%>%
  filter(test == if_else(max(test) >= 60, test == min(test), test == max(test)))

and

data1 = data%>%
  filter(Date == max(Date))%>%
  if_else(max(test) >= 60, filter(test == min(test)), filter(test == max(test)))

None of these work, though logically I think they should. I get errors for all of them.

Created on 2020-11-18 by the reprex package (v0.3.0)

Upvotes: 0

Views: 67

Answers (1)

Ronak Shah
Ronak Shah

Reputation: 389155

To solve your approach use if/else since this is a scalar comparison.

library(dplyr)
data%>%
  filter(Date == max(Date)) %>%
  filter(if(max(test) >= 60) test == min(test) else test == max(test))

#  ID       Date     test
#1 12 2020-07-01 78.43785

Upvotes: 2

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