R help - Feb 2011 - copy values from one dataframes into another

Hello everyone,

I have the following problem, I have a dataframes that looks like this:

  fire$Year fire$Size
1      1981    1738.0
2      1984    2228.1
3      1985   38963.3
4      1986    2223.4
5      1987    3594.6
6      1988    1520.0
...

What I would like to do is copy the values from the fire$Size colum and put
it into a new df but with "0" for the years that are missing. The
result
should look like this:

year  size

1981  1738.0
1982      0
1983      0
1984  2228.1
...

First I tried to merge the two dataframes 
 temp <-merge(fire.sum,fire2, by.x="fire$Year",
by.y="year")

but then it only gives me the years that are the same. So I thought it might
be easier to just copy them?

Any help is appreciated, thank you so much
Cheers
Sandra

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What you want to do is create a new dataframe that includes all the years.
> newdata <- data.frame( Year=1981:1988 )
> merge(fire, newdata, all=TRUE)
If you don't include the all=TRUE, then you only get the rows that are
contained in both datasets.
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Hi Sandra, 

Terribly ugly, but this way at least you don't have to know which years are
missing, etc.:


dat <- data.frame(year = c(1981,1984,1985,1986), size = c(1,2,3,4))
year_ <- data.frame(year = seq(1981,1986,1))
year_dat <- merge(year_, dat, by = "year", all=T)
na_s <- subset(year_dat, is.na(size) == "TRUE")
na_s_zeros <- cbind(na_s, size = rep(0, length(na_s[,1])))[,-2]

newdat <- rbind(subset(year_dat, !is.na(size) == "TRUE"),
na_s_zeros)



hth,
Scott
On Wednesday, February 23, 2011 at 4:22 PM, saba wrote: 
> 
> Hello everyone,
> 
> I have the following problem, I have a dataframes that looks like this:
> 
>  fire$Year fire$Size
> 1 1981 1738.0
> 2 1984 2228.1
> 3 1985 38963.3
> 4 1986 2223.4
> 5 1987 3594.6
> 6 1988 1520.0
> ...
> 
> What I would like to do is copy the values from the fire$Size colum and put
> it into a new df but with "0" for the years that are missing. The
result
> should look like this:
> 
> year size
> 
> 1981 1738.0
> 1982 0
> 1983 0
> 1984 2228.1
> ...
> 
> First I tried to merge the two dataframes 
>  temp <-merge(fire.sum,fire2, by.x="fire$Year",
by.y="year")
> 
> but then it only gives me the years that are the same. So I thought it
might
> be easier to just copy them?
> 
> Any help is appreciated, thank you so much
> Cheers
> Sandra
> 
> -- 
> View this message in context:
http://r.789695.n4.nabble.com/copy-values-from-one-dataframes-into-another-tp3321805p3321805.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
> 
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