Create an empty data.frame

dataframe, r, r-faq

Solution

Just initialize it with empty vectors:

df <- data.frame(Date=as.Date(character()),
                 File=character(), 
                 User=character(), 
                 stringsAsFactors=FALSE)

Here's an other example with different column types :

df <- data.frame(Doubles=double(),
                 Ints=integer(),
                 Factors=factor(),
                 Logicals=logical(),
                 Characters=character(),
                 stringsAsFactors=FALSE)

str(df)
> str(df)
'data.frame':   0 obs. of  5 variables:
 $ Doubles   : num 
 $ Ints      : int 
 $ Factors   : Factor w/ 0 levels: 
 $ Logicals  : logi 
 $ Characters: chr

N.B. :

Initializing a `data.frame` with an empty column of the wrong type does not prevent further additions of rows having columns of different types. This method is just a bit safer in the sense that you'll have the correct column types from the beginning, hence if your code relies on some column type checking, it will work even with a `data.frame` with zero rows.

Problem

I'm trying to initialize a data.frame without any rows. Basically, I want to specify the data types for each column and name them, but not have any rows created as a result. The best I've been able to do so far is something like: ``` df <- data.frame(Date=as.Date("01/01/2000", format="%m/%d/%Y"), File="", User="", stringsAsFactors=FALSE) df <- df[-1,] ``` Which creates a data.frame with a single row containing all of the data types and column names I wanted, but also creates a useless row which then needs to be removed. Is there a better way to do this?

Original source