Remove Rows From Data Frame where a Row matches a String

You can use the dplyr package to easily remove those particular rows.

library(dplyr)
df <- filter(df, C != "Foo")

if you wish to using dplyr, for to remove row "Foo":

df %>%
 filter(!C=="Foo")

I had a column(A) in a data frame with 3 values in it (yes, no, unknown). I wanted to filter only those rows which had a value "yes" for which this is the code, hope this will help you guys as well --

df <- df [(!(df$A=="no") & !(df$A=="unknown")),]

Just use the == with the negation symbol (!). If dtfm is the name of your data.frame:

dtfm[!dtfm$C == "Foo", ]

Or, to move the negation in the comparison:

dtfm[dtfm$C != "Foo", ]

Or, even shorter using subset():

subset(dtfm, C!="Foo")