Reshape data.frame with two columns into multiple columns with data (R)

Question

A trivial question but I cant find the answer as of yet. I want to split the dataframe column 'year' into a set of new columns with each year the column name and subsequent data below it: ``` Year FQ 1975 3.156 1975 8.980 1977 10.304 1977 7.861 1979 4.729 1979 7.216 1981 4.856 1981 3.438 1983 9.887 1983 3.850 ``` desired output: ``` 1975 1977 1979 1981 1983 3.156 10.304 4.729 4.856 9.887 8.980 7.861 7.216 3.438 3.850 ``` sample data: ``` d<-structure(list(Year = structure(1:10, .Label = c("1975", "1975", "1977", "1977", "1979", "1979", "1981", "1981", "1983", "1983", "1985", "1985", "1987", "1987", "1988", "1988", "1991", "1991", "1993", "1993", "1995", "1995", "1997", "1997", "2000", "2000", "2001", "2001", "2003", "2003", "2005", "2005", "2007", "2007", "2009", "2009", "2011", "2011"), class = "factor"), FQ = c(3.156, 8.98, 10.304, 7.861, 4.729, 7.216, 4.856, 3.438, 9.887, 3.85)), .Names = c("Year", "FQ"), class = "data.frame", row.names = c(1L, 62L, 123L, 184L, 245L, 306L, 367L, 42…

Accepted Answer

You don't really have an "ID" variable, so you need to create one. It will be easier if `Year` was a `character` variable, so I've done that transformation below, in addition to adding an "ID" variable:

```
d <- within(d, {
  Year <- as.character(Year)
  ID <- ave(Year, Year, FUN=seq_along)
})
```

From here, it is easy to use `dcast` directly...

```
library(reshape2)
dcast(d, ID ~ Year, value.var="FQ")
#   ID  1975   1977  1979  1981  1983
# 1  1 3.156 10.304 4.729 4.856 9.887
# 2  2 8.980  7.861 7.216 3.438 3.850
```

... or `reshape`.

```
reshape(d, direction  = "wide", idvar="ID", timevar="Year")
#    ID FQ.1975 FQ.1977 FQ.1979 FQ.1981 FQ.1983
# 1   1   3.156  10.304   4.729   4.856   9.887
# 62  2   8.980   7.861   7.216   3.438   3.850
```

Reshape data.frame with two columns into multiple columns with data (R)

Solution

Problem