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.
--
David.
-N
On 11/11/10 2:02 PM, Peter Langfelder wrote:
On Thu, Nov 11, 2010 at 1:19 PM, William Dunlap <wdun...@tibco.com>
wrote:
Peter,
Your example doesn't work for me unless I
set options(stringsAsFactors=TRUE) first.
(If I do set that, then all columns of 'results'
have class "character", which I doubt the user
wants.)
You probably mean stringsAsFactors=FALSE.
What you say makes sense, because the c() function produces a vector
in which all components have the same type, wnd it will be character.
If you don't want to have characters, my solution would be
n = 10
results <- data.frame(a = rep("", n), b = rep(0, n), c = rep(0, n), d
= rep(0, n))
for(i in 1:n){
a = LETTERS[i];
b = i;
c = 3*i + 2
d = rnorm(1);
results$a[i] = a
results$b[i] = b
results$c[i] = c
results$d[i] = d
}
results
a b c d
1 A 1 5 -1.31553805
2 B 2 8 0.09198054
3 C 3 11 -0.05860804
4 D 4 14 0.77796136
5 E 5 17 1.28924697
6 F 6 20 0.47631483
7 G 7 23 -1.23727076
8 H 8 26 0.83595295
9 I 9 29 0.69435349
10 J 10 32 -0.30922930
mode(results[, 1])
[1] "character"
mode(results[, 2])
[1] "numeric"
mode(results[, 3])
[1] "numeric"
mode(results[, 4])
[1] "numeric"
or alternatively
n = 10
num <- data.frame(b = rep(0, n), c = rep(0, n), d = rep(0, n))
labels = rep("", n);
for(i in 1:n){
a = LETTERS[i];
b = i;
c = 3*i + 2
d = rnorm(1);
labels[i] = a
num[i, ] = c(b, c, d)
}
results = data.frame(a = labels, num)
results
a b c d
1 A 1 5 -0.47150097
2 B 2 8 -1.30507313
3 C 3 11 -1.09860425
4 D 4 14 0.91326330
5 E 5 17 -0.09732841
6 F 6 20 -0.75134162
7 G 7 23 0.31360908
8 H 8 26 -1.54406716
9 I 9 29 -0.36075743
10 J 10 32 -0.23758269
mode(results[, 1])
[1] "character"
mode(results[, 2])
[1] "numeric"
mode(results[, 3])
[1] "numeric"
mode(results[, 4])
[1] "numeric"
Peter
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______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
