Appending data frames¶
First we load some example data from the British Election Study 2010. The data set bes2010feelings-for-append.RData is prepared from the original available at https://www.britishelectionstudy.com/data-object/2010-bes-cross-section/ by removing identifying information and scrambling the data.
load("bes2010feelings-for-append.RData")
We now have two BES data frames, one from the pre-election wave and another from the post-election wave. They contain the same variables, but in a different order:
str(bes2010flngs_pre)
'data.frame': 1935 obs. of 14 variables:
$ flng.brown : num 6 3 8 4 5 5 5 4 7 4 ...
$ flng.cameron: num 3 7 7 4 5 0 3 6 2 2 ...
$ flng.clegg : num 3 5 4 3 5 4 2 7 4 8 ...
$ flng.salmond: num NA NA NA NA NA NA NA NA NA NA ...
$ flng.jones : num 5 3 10 7 5 1 7 1 6 4 ...
$ flng.labour : num 5 1 3 6 8 5 6 2 8 3 ...
$ flng.cons : num 6 6 4 6 4 1 3 3 3 3 ...
$ flng.libdem : num 4 7 5 5 5 4 0 5 4 9 ...
$ flng.snp : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.pcym : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.green : num 7 6 5 5 4 4 1 5 5 5 ...
$ flng.ukip : num 3 0 0 3 NA 0 NA 2 3 1 ...
$ flng.bnp : num 0 0 0 2 2 0 0 0 0 0 ...
$ region : Factor w/ 3 levels "England","Scotland",..: 1 NA 1 1 NA 1 1 1 1 1 ...
str(bes2010flngs_post)
'data.frame': 3075 obs. of 14 variables:
$ flng.jones : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.labour : num 5 2 9 7 0 2 6 5 7 2 ...
$ flng.ukip : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.libdem : num 4 5 4 4 6 NA 4 4 7 7 ...
$ flng.brown : num 5 2 5 7 0 2 3 2 5 2 ...
$ flng.bnp : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.snp : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.salmond: num NA NA NA NA NA NA NA NA NA NA ...
$ flng.pcym : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.cons : num 5 5 3 10 10 3 3 8 7 7 ...
$ flng.cameron: num 5 6 5 3 8 10 7 8 8 7 ...
$ flng.green : num NA NA NA NA NA NA NA NA NA NA ...
$ flng.clegg : num NA 4 3 NA 6 3 5 4 7 6 ...
$ region : Factor w/ 3 levels "England","Scotland",..: 1 1 1 1 1 1 1 1 1 1 ...
If the variables in the two data frames differ trying to use rbind() to append
the data frames fails.
bes2010flngs_prepost <- rbind(bes2010flngs_pre[-1],
bes2010flngs_post[-1])
Error in match.names(clabs, names(xi)):
names do not match previous names
Traceback:
1. rbind(bes2010flngs_pre[-1], bes2010flngs_post[-1])
2. rbind(deparse.level, ...)
3. match.names(clabs, names(xi))
4. stop("names do not match previous names")
If the variables in the two data frame are the same but differ in their order,
rbind() succeeds and the variables are sorted all into the same order before the
data frames are combined into a single one:
bes2010flngs_prepost <- rbind(bes2010flngs_pre,
bes2010flngs_post)
We compare the tail-ends of the data resulting data frame
bes2010flngs_prepost and the data frame given as second argument to
rbind. The tail-ends are identical except for the order of the
variables.
options(width=200)
tail(bes2010flngs_prepost)
flng.brown flng.cameron flng.clegg flng.salmond flng.jones flng.labour flng.cons flng.libdem flng.snp flng.pcym flng.green flng.ukip flng.bnp region
79219.2 2 8 7 NA 5 3 8 7 NA 6 6 4 0 Wales
79220.2 0 5 5 NA 4 3 5 4 NA 3 1 0 1 Wales
79621.2 8 4 7 NA 5 7 4 6 NA 3 4 4 4 Wales
79622.2 8 5 3 NA 6 8 5 4 NA 6 7 4 1 Wales
80019.2 5 8 6 NA 5 3 7 5 NA 5 3 6 5 Wales
80020.2 7 6 8 NA 6 7 6 7 NA 5 5 2 0 Wales
tail(bes2010flngs_post)
flng.jones flng.labour flng.ukip flng.libdem flng.brown flng.bnp flng.snp flng.salmond flng.pcym flng.cons flng.cameron flng.green flng.clegg region
79219.2 5 3 4 7 2 0 NA NA 6 8 8 6 7 Wales
79220.2 4 3 0 4 0 1 NA NA 3 5 5 1 5 Wales
79621.2 5 7 4 6 8 4 NA NA 3 4 4 4 7 Wales
79622.2 6 8 4 4 8 1 NA NA 6 5 5 7 3 Wales
80019.2 5 3 6 5 5 5 NA NA 5 7 8 3 6 Wales
80020.2 6 7 2 7 7 0 NA NA 5 6 6 5 8 Wales
- R file: appending.R
- Rmarkdown file: appending.Rmd
- Jupyter notebook file: appending.ipynb
- Interactive version of the Jupyter notebook (shuts down after 60s):
- Interactive version of the Jupyter notebook (sign in required):
