CODEWITHSUNDEEP
rdataframe
ahs85
ahs85

Reputation: 1977

Rbind same data.frame with column switching

I am not new to R, but I cannot solve this problem: I have a data.frame and want to rbind the same data.frame with coloumn switching. But R does not switch the columns.

Example:

set.seed(13)
df <- data.frame(var1 = sample(5), var2 = sample(5))
> df
  var1 var2
1    4    1
2    1    3
3    2    4
4    5    2
5    3    5

> rbind(df, df[,c(2,1)])
   var1 var2
1     4    1
2     1    3
3     2    4
4     5    2
5     3    5
6     4    1
7     1    3
8     2    4
9     5    2
10    3    5

As you can see, the coloumns are not switched (row 6-10) whereas switching the columns alone works like a charm:

> df[,c(2,1)]
  var2 var1
1    1    4
2    3    1
3    4    2
4    2    5
5    5    3

I guess this has something to do with the column names, but I cannot figure out what exacly.

Can anyone help?

Kind regards!

Upvotes: 1

Views: 309

Answers (1)

Jilber Urbina
Jilber Urbina

Reputation: 61154

As pointed out by @Henrik, from ?rbind.data.frame: "The rbind data frame method [...] matches columns by name. So try this:

> rbind(df, setNames(df[,c(2,1)], c("var1", "var2")))
   var1 var2
1     4    1
2     1    3
3     2    4
4     5    2
5     3    5
6     1    4
7     3    1
8     4    2
9     2    5
10    5    3

this also works:

> rbind(as.matrix(df), as.matrix(df[,c(2,1)]))

Upvotes: 2

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