Delete zero rows from a table in R

Question

I had two data frames one with information about ProductId, Price, Location and other data frame with ProductId and Name. So I merged them together using following command.

DF1$Name <- names$Name[match(DF1$ProductId,names$ProductId)];

And it worked fine. Then I took a subset of the DF1 based on certain Location like this

DF_London = subset(DF1, Location == "London")

In DF1 Names had 100 Levels, In DF_London it should have 25 Levels and by using unique and length I can see it. But in str(DF_London) it shows 100 Levels of Names and when i try to draw table like

with(DF_London,table(Names, Price)

It shows a table with 100 rows and many of these rows have all zero values because obviously those names don't exist in DF_London data frame.

So how can I either fix the number of Level for Names in DF_London or delete the zero rows?

Sorry for not providing the reproducible example.

Maybe you could take a look at `?droplevels`. – RHertel Apr 09 '16 at 06:09 — RHertel, Apr 09 '16 at 06:09
@RHertel thanks. it helped. – Jay khan Apr 09 '16 at 06:13 — Jay khan, Apr 09 '16 at 06:13

score 1 · Accepted Answer · answered Apr 09 '16 at 06:15

1

DF_London$Names <- droplevels(DF_London$Names)

answered Apr 09 '16 at 06:15

Jay khan

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Delete zero rows from a table in R

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