Specifying Column Labels in a data.frame changes spaces to "."

Question

Let's say I have a data.frame, like so:

x <- c(1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10)
df <- data.frame("Label 1"=x,"Label 2"=rnorm(100))

head(df,3)

returns:

  Label.1    Label.2
1       1  1.9825458
2       2 -0.4515584
3       3  0.6397516

How do I get R to stop automagically replacing the space with a period in the column label? ie, "Label 1" instead of "Label.1".

Answer 1

You don't.

With the space you desire the format would not satisfy the requirements for an identifier that come to play when you use df$column.1 -- that could not cope with a space. So see the make.names() function for details or an example:

> make.names(c("Foo Bar", "tic tac"))
[1] "Foo.Bar" "tic.tac"  
>                                              

Answer 2

You can change an existing data frames names to contain spaces ie using your example

x <- c(1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10)
df <- data.frame("Label 1"=x,"Label 2"=rnorm(100))
colnames(df) <- c("Label 1", "Label 2")
head(df, 3)

returns

  Label 1    Label 2
1       1  0.2013347
2       2  1.8823111
3       3 -0.5233811

and you can still access the columns using the $ operator, you just need to use double quotes eg

df$"Label 2"[1:3]

returns

[1]  0.2013347  1.8823111 -0.5233811

It seems rather inconsistent to me to auto-convert column names upon data.frame creation, but not to-do the same during column name alteration, but thats how R works at the moment.

Answer 3

I found a solution as well:

x <- c(1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10,1:10)
df <- data.frame("Label 1"=x,"Label 2"=rnorm(100), check.names=F)

returns:

  Label 1    Label 2
1       1  0.2013347
2       2  1.8823111
3       3 -0.5233811

Adding check.names=F argument worked out.