[R] new column from column in another df

[jim holtman]

?merge

> df1
                 V1 V2
1   Populus tremula  1
2   Populus tremula  2
3   Populus tremula  3
4  Calluna vulgaris  1
5  Calluna vulgaris  2
6       Betula alba  1
7       Betula alba  2
8       Betula alba  3
9     Primula veris  1
10    Primula veris  2
> df2 <- read.table('clipboard', sep=',')
> df2
                V1          V2
1  Populus tremula        tree
2 Acer platanoides        tree
3     Ribes rubrum       shrub
4 Calluna vulgaris dwarf_shrub
5      Betula alba        tree
6    Primula veris        herb
> merge(df1, df2, by = "V1")
                 V1 V2.x        V2.y
1       Betula alba    1        tree
2       Betula alba    2        tree
3       Betula alba    3        tree
4  Calluna vulgaris    1 dwarf_shrub
5  Calluna vulgaris    2 dwarf_shrub
6   Populus tremula    1        tree
7   Populus tremula    2        tree
8   Populus tremula    3        tree
9     Primula veris    1        herb
10    Primula veris    2        herb
>


On Tue, Nov 9, 2010 at 7:28 AM, fugelpitch <jonas at runtimerecords.net> wrote:
>
> If I have a data frame where a species occupies several rows with different
> phases such as (both col's ar factors):
> species,phase
> Populus tremula,1
> Populus tremula,2
> Populus tremula,3
> Calluna vulgaris,1
> Calluna vulgaris,2
> Betula alba,1
> Betula alba,2
> Betula alba,3
> Primula veris,1
> Primula veris,2
>
> and another df where each species only have one row:
> species,growth_form
> Populus tremula,tree
> Acer platanoides,tree
> Ribes rubrum,shrub
> Calluna vulgaris,dwarf_shrub
> Betula alba,tree
> Primula veris,herb
>
> ...how can I create a new column in the first data frame where growth form
> is picked up from the second data frame (also factors) and entered into all
> rows for a species as follows:
> species,phase,growth_form
> Populus tremula,1,tree
> Populus tremula,2,tree
> Populus tremula,3,tree
> Calluna vulgaris,1,dwarf_shrub
> Calluna vulgaris,2,dwarf_shrub
> Betula alba,1,tree
> Betula alba,2,tree
> Betula alba,3,tree
> Primula veris,1,herb
> Primula veris,2,herb
>
> This will be made for data frames a lot larger than this one so it needs to
> be automated in some way.
> Also, as you can see the second data frame contains more species than the
> first one so I need to pick them out by name not only by row number...
>
> (I tried something like:
> subset(dataframe2.df,
> dataframe2.df$species==as.character(unique(dataframe1.df$species)))
> in a for loop but I got an error about different factor levels which is
> true.)
>
>
> Any help is very appreciated!
>
> Jonas
> --
> View this message in context: http://r.789695.n4.nabble.com/new-column-from-column-in-another-df-tp3033619p3033619.html
> Sent from the R help mailing list archive at Nabble.com.
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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