David,
Great solution. While a bit longer to enter, it lets me explicitly
define a type for each column.
Thanks!!!
-N
On 11/11/10 4:02 PM, David Winsemius wrote:
>
> On Nov 11, 2010, at 6:38 PM, Noah Silverman wrote:
>
>> That makes perfect sense. All of my numbers are being coerced into
>> strings by the c() function. Subsequently, my data.frame contains all
>> strings.
>>
>> I can't know the length of the data.frame ahead of time, so can't
>> predefine it like your example.
>> One thought would be to make it arbitrarily long filled with 0 and
>> delete off the unused rows. But this seems rather wasteful.
>
> Although it might be faster, though. Here is a non-c() method using
> instead the list function (with options(stringsAsFactors=FALSE). List
> does not coerce to same mode and rbind.dta.frame will accept a list as
> a row argument:
>
> results <- data.frame(a=vector(mode="character", length=0) ,
> b=vector(mode="numeric", length=0),
> cc=vector(mode="numeric", length=0), # note:
> avoid "c" as name
> d=vector(mode="numeric", length=0))
> n = 10
> for(i in 1:n){
> a = LETTERS[i];
> b = i;
> cc = 3*i + 2
> d = rnorm(1);
> results <- rbind(results, list(a=a,b=b,cc=cc,d=c))
> }
> results
> a b cc d
> 2 A 1 5 5
> 21 B 2 8 8
> 3 C 3 11 11
> 4 D 4 14 14
> 5 E 5 17 17
> 6 F 6 20 20
> 7 G 7 23 23
> 8 H 8 26 26
> 9 I 9 29 29
> 10 J 10 32 32
>
> OOOPs used d=c and there was a "c" vector hanging around to be picked up.
>
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