CODEWITHSUNDEEP
r
RobP
RobP

Reputation: 11

remove rows of specified levels of factor from dataframe

I have what may be a very simple problem to solve in R, but I've been struggling with it for a while without finding an adequate solution.

From the following dataframe, I just need to fully remove any row that contains 'U' for Sex, whilst also removing the level 'U' from factor Sex. And I would also like the ability to remove any ID of my choosing by specifying a vector of ID numbers. My actual dataset is much larger than this. 

datf <- read.table(text = "ID   Sex Mor SITE
                           110   F   W    1
                           111   M   W    2
                           112   M   B    4
                           135   F   W    3
                           556   M   B    1
                           557   U   B    1
                           558   M   W    2",
                   header = TRUE)

I thought I would be able to work this out, but I have tried various methods suggested on this website such as droplevels- but I can't seem to figure it out. Thanks very much in advance for your help!

Upvotes: 0

Views: 10482

Answers (1)

Patricio Moracho
Patricio Moracho

Reputation: 717

  • Remove rows with Sex == 'U' and drop level

    datf <- droplevels(datf[!datf$Sex == 'U',])
str(datf)

'data.frame':   6 obs. of  4 variables:
 $ ID  : int  110 111 112 135 556 558
 $ Sex : Factor w/ 2 levels "F","M": 1 2 2 1 2 2
 $ Mor : Factor w/ 2 levels "B","W": 2 2 1 2 1 2
 $ SITE: int  1 2 4 3 1 2

  • Remove any row where ID in vector

    datf <- datf[!(datf$ID %in% c(110, 558)),]
datf

   ID Sex Mor SITE
2 111   M   W    2
3 112   M   B    4
4 135   F   W    3
5 556   M   B    1

Upvotes: 3

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