Remove Rows From Data Frame where a Row matches a String

Question

I do I remove all rows in a dataframe where a certain row meets a string match criteria?

For example:

A,B,C
4,3,Foo
2,3,Bar
7,5,Zap

How would I return a dataframe that excludes all rows where C = Foo:

A,B,C
2,3,Bar
7,5,Zap

Related question: [Deleting specific rows from a data frame](http://stackoverflow.com/questions/6601658/deleting-specific-rows-from-a-data-frame). — Joshua Ulrich, Jul 11 '11 at 13:13

score 119 · Accepted Answer · edited May 01 '16 at 05:31

119

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")

edited May 01 '16 at 05:31

Riad

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answered Jul 11 '11 at 13:09

Luciano Selzer

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4

Or just `dftm[dtfm$C != "Foo", ]` which is the same but slightly more easier to read. – Sacha Epskamp Jul 11 '11 at 13:19
6

.. or `subset(dftm, C!="Foo")` – Karsten W. Jul 11 '11 at 14:01
1

How would you do this with an arbitrary number of conditions? Like if you wanted to remove all rows where "C = Foo" or "C = Bar"? – Zelbinian Mar 05 '13 at 15:11
5

That would be another question. But the key is to use %in% and !. In your example !(C %in% c("Foo", "Bar")) – Luciano Selzer Mar 05 '13 at 16:55
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All good feedback. To complete Luciano's suggestion for the non-subset() example, I found that this worked to trim out undesired rows: dtfm – Robert Casey Feb 18 '14 at 21:11

score 12 · Answer 2 · answered Nov 14 '17 at 09:38

12

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

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

answered Nov 14 '17 at 09:38

Pranesh Krishnamurthy

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score 1 · Answer 3 · edited Apr 17 '18 at 21:50

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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")),]

edited Apr 17 '18 at 21:50

Jason Roman

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answered Apr 17 '18 at 21:32

Pratik Honrao

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score 1 · Answer 4 · answered Jan 07 '21 at 19:59

1

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

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

answered Jan 07 '21 at 19:59

wesleysc352

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score 0 · Answer 5 · edited May 04 '22 at 16:05

0

I know this has been answered but here is another option:

library (dplyr)
df %>% filter(!c=="foo)

OR

df[!df$c=="foo", ]

edited May 04 '22 at 16:05

AndrewGB

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answered Jan 02 '22 at 05:41

Humza Iftikhar

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Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jan 02 '22 at 08:28

score 0 · Answer 6 · answered May 11 '22 at 16:50

If your exclusion conditions are stored in another data frame you could use rows_delete:

library(dplyr)

removal_df <- data.frame(C = "Foo")

df %>% 
  rows_delete(removal_df, by = "C")

  A B   C
1 2 3 Bar
2 7 5 Zap

This is also handy if you have multiple exclusion conditions so you do not have to write out a long filter statement.

Note: rows_delete is only available if you have dplyr >= 1.0.0

Remove Rows From Data Frame where a Row matches a String

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