memy - 1 year ago 147
R Question

# remove some rows in dataframe

I have a data frame

``````      mydata <- data.frame(
x1= as.factor(1:3),
x2= as.factor (4:6),
x3= as.factor(7:9),
x4= as.factor (2:7),
x5= as.factor(1:6),
x6= seq(0,600,len= 600),
x7= seq(0,1,len=600)
)
``````

and I want to remove some rows in this with particular conditions. I did in this way:

``````mydata1 <- mydata%>%
filter(x1==1, x2==4, x3==7, x4==2, x5==1)%>%
anti_join(mydata,., by=c("x1", "x2", "x3", "x4","x5","x6" "x7"))

mydata2 <- mydata1%>%
filter(x1==3, x2==6 x3==9, x4==7, x5==6)%>%
anti_join(mydata1,., by=c("x1", "x2", "x3", "x4","x5","x6", "x7"))
``````

There are a lot of rows that I want to remove, is there another way to do this?

You can combine logical tests with `&` for and and `|` for or. If you want to remove rows that meet all of the following

``````x1==1, x2==4, x3==7, x4==2, x5==1
``````

Then do it like this:

``````filter(mydata, !(x1 == 1 & x2 == 4 & x3 == 7 & x4 == 2 & x5 == 1))
``````

The row order is different, but the results are the same:

``````md1 = filter(mydata, !(x1 == 1 & x2 == 4 & x3 == 7 & x4 == 2 & x5 == 1))
identical(arrange(md1, x6), arrange(mydata1, x6))
# [1] TRUE
``````

You can combine your conditions into one `filter` this way:

``````md2 = filter(
mydata,
!(x1 == 1 & x2 == 4 & x3 == 7 & x4 == 2 & x5 == 1),
!(x1 == 3 & x2 == 6 & x3 == 9 & x4 == 7 & x5 == 6)
)
``````
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