How to extract rows from dataframe by factors?

Asked Feb 17 '19 at 12:25

Active Feb 17 '19 at 12:25

Viewed 25 times

I have a dataframe, and now I would like to extract some rows by a column content. For example:

name <- c("John","Lily","Cat","King")
record <- c(2,6,10,3)
dftry <- data.frame(name,record)
list <- c("John","cat")

I want to extract the row which dftry$name == "John" | "cat" (which is in the list) how can I do that? I have tried

dftry[dftry$name==list,]  #but this do not gonna work
dftry[which(dftry$name == "John"| dftry$name =="Cat"),]  #this would work but the real list is thousands long than 2.

So how can I do it easily? Thank you

asked Feb 17 '19 at 12:25

Codezy

2

Try `dftry[dftry$name %in% list,]`. – jay.sf Feb 17 '19 at 12:28
You can try `subset(dftry, name %in% list)`. – tmfmnk Feb 17 '19 at 12:29
@jay.sf you are the day saver. Could u tell me what is this %in% and convert this to an answer？ – Codezy Feb 17 '19 at 12:30
@Codezy If you're not sure what something in R is, first try the help file, in this case by running `help("%in%")` – duckmayr Feb 17 '19 at 12:44
1

@Codezy It's actually `match()` type `?"%in%"`. – jay.sf Feb 17 '19 at 12:44
@duckmayr learned it thank you – Codezy Feb 19 '19 at 14:40
@jay.sf yeah thank you I also figured it out – Codezy Feb 19 '19 at 14:41

How to extract rows from dataframe by factors?

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