[R] integer and character conversion

[David Winsemius]

On Aug 22, 2009, at 6:13 PM, Dajiang J. Liu wrote:

> Dear all,I want to convert a long integer to a string, and for  
> example,
> 100000000
> I used as.character(1000000000) e.g, and it gives me back 1e+???.  
> What I
> want is a exact form, not exponential form. Any ideas how to do it?  
> Thank

The numeric ("double") type is not "exact" in R. (Read the FAQ) You  
can specify an integer by appending an "L" but that will limit the  
magnitude.

 > 1000000000L
[1] 1000000000

 > 10000000000L
[1] 1e+10
Warning message:
non-integer value 10000000000 qualified with L; using numeric value

You are supposed to have control of the length of displayed decimal  
numbers with the option for "digits" but it doesn't work for me:

 > options("digits" = 12)
 > print(1000000000)
[1] 1e+09
 > 1000000000
[1] 1e+09

-- 
David Winsemius