Subset a dataframe using 2 columns with a condition in R

Question

I have a dataframe like this:

ID <- c("A","B","C","D","E","F","G","H","I")
Measurement <- c('Length',NA,NA,NA,'Length','Length',NA,NA,'Length')
PT <- c(27,35,38,22,35,39,7,15,33)
df <- data.frame(ID,Measurement,PT)
Limit <- 25

I am trying to subset this dataframe using the limit as the condition so that I exclude any data that has a ("PT" value > limit AND Measuremnent = NA).

Note: However I still want to include any data that has PT > Limit but with a Measurement type in it. In this case, its the length.

I am trying to do it this way but I get an error

df3 <- !subset(df3,df3$PT >= Limit & df3$Measurement == '')

My desired Output is

  ID Measurement PT
1  A      Length 27
2  D        <NA> 22
3  E      Length 35
4  F      Length 39
5  G        <NA>  7
6  H        <NA> 15
7  I      Length 33

I know this is pretty simple but I missing the logic somewhere. Could someone point me in the right direction?

Are you looking for df[!is.na(df$Measurement) | df$PT < Limit,]? — josliber
– josliber, Commented Dec 9, 2015 at 2:28
@josilber, fantastic. Exactly does what I wanted. I took your solution to my bigger data set and works like charm. Thank you so much :-) — Sharath
– Sharath, Commented Dec 9, 2015 at 2:51

akrun · Accepted Answer · 2015-12-09 02:59:36Z

1

We can also do

df[with(df, !(PT> Limit & is.na(Measurement))),]
#  ID Measurement PT
#1  A      Length 27
#4  D        <NA> 22
#5  E      Length 35
#6  F      Length 39
#7  G        <NA>  7
#8  H        <NA> 15
#9  I      Length 33

Or using dplyr

library(dplyr)
df %>%
   filter(!(PT > Limit & is.na(Measurement)))

answered Dec 9, 2015 at 2:59

akrun

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1 Comment

Sharath Over a year ago

Wanted a dplyr solution as well. Thanks much akrun.

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