creating a factor

Simon Hosking <simon.hosking at general.monash.edu.au> writes:

Hi list,
I'd like to make a factor with seven 1s and three 2s using the
factor() function. 
That is,

1
1
1
1
1
1
1
2
2
2
 

I will then bind this factor to the matrix below using cbind.data.frame().

0.56	0.48
0.22	0.59
0.32	0.64
0.26	0.60
0.25	0.38
0.24	0.45
0.56	0.67
0.78	0.97
0.87	0.79
0.82	0.85



I am new to R and have been using various manuals and have made many attempts without success
any help appreciated.
thanks,
Simon

f <- factor(scan())

1: 1
2: 1
3: 1
4: 1
5: 1
6: 1
7: 1
8: 2
9: 2
10: 2
11:
Read 10 items

df <- read.table(stdin())

0: 0.56 0.48
1: 0.22 0.59
2: 0.32 0.64
3: 0.26 0.60
4: 0.25 0.38
6: 0.24 0.45
7: 0.56 0.67
8: 0.78 0.97
9: 0.87 0.79
10: 0.82 0.85
11:

cbind(df,f)

V1   V2 f
1  0.56 0.48 1
2  0.22 0.59 1
3  0.32 0.64 1
4  0.26 0.60 1
5  0.25 0.38 1
6  0.24 0.45 1
7  0.56 0.67 1
8  0.78 0.97 2
9  0.87 0.79 2
10 0.82 0.85 2

summary(cbind(df,f))

V1               V2         f
 Min.   :0.2200   Min.   :0.3800   1:7
 1st Qu.:0.2525   1st Qu.:0.5075   2:3
 Median :0.4400   Median :0.6200
 Mean   :0.4880   Mean   :0.6420
 3rd Qu.:0.7250   3rd Qu.:0.7600
 Max.   :0.8700   Max.   :0.9700


so what was the problem?? 

I suspect your df was a matrix, not a data frame: just take
as.data.frame first. Otherwise, you'll find that f gets converted to
numeric.

O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907