R - Concatenate two dataframes?
Given two dataframes a and b:
> a
a b c
1 -0.2246894 -1.48167912 -1.65099363
2 0.5559320 -0.87898575 -0.15634590
3 1.8469466 -0.01487524 -0.53098215
4 -0.6875051 0.23880967 0.01824621
5 -0.6735163 0.75485292 0.44154092
> b
a c
1 0.4287284 -0.3295925
2 0.5201492 0.3341251
3 -2.6355570 1.7916780
4 -1.3645337 1.3642276
5 -0.4954542 -0.6660001
Is there a simple way to concatenate these so as to return a new data frame of the form below?
> new
a b c
1 -0.2246894 -1.48167912106676 -1.65099363
2 0.5559320 -0.878985746842256 -0.15634590
3 1.8469466 -0.0148752354840942 -0.53098215
4 -0.6875051 0.238809666690982 0.01824621
5 -0.6735163 0.754852923524198 0.44154092
6 0.4287284 NA -0.32959248
7 0.5201492 NA 0.33412510
8 -2.6355570 NA 1.79167801
9 -1.3645337 NA 1.36422764
10 -0.4954542 NA -0.66600006
I want to merge the dataframes, match the headers and insert NA in for positions in dataframe b where the header is missing.
Answer
You want "rbind".
b$b <- NA
new <- rbind(a, b)
rbind requires the data frames to have the same columns.
The first line adds column b to data frame b.
Results
> a <- data.frame(a=c(0,1,2), b=c(3,4,5), c=c(6,7,8))
> a
a b c
1 0 3 6
2 1 4 7
3 2 5 8
> b <- data.frame(a=c(9,10,11), c=c(12,13,14))
> b
a c
1 9 12
2 10 13
3 11 14
> b$b <- NA
> b
a c b
1 9 12 NA
2 10 13 NA
3 11 14 NA
> new <- rbind(a,b)
> new
a b c
1 0 3 6
2 1 4 7
3 2 5 8
4 9 NA 12
5 10 NA 13
6 11 NA 14