Hi,

I am still new to R and this is my first post on this mailing-list.

I have two .csv (each one being a column of real numbers) coming from the
same database (the first one is just longer than the second) and I read them
in R the following way:

returns  <- read.csv("test.csv", header = FALSE)
returns2  <- read.csv("test2.csv", header = FALSE)

However, the two objects clearly don't seem to be equivalent:

> returns[2528:2537,1]
 [1] -0.002206 0.115696  -0.015192 0.008719  -0.004654 -0.010688 0.009453
0.002676  0.001334  -0.011326
7470 Levels: -0.000078 -0.000085 -0.000086 -0.0001 -0.000112 -0.000115
-0.000152 -0.000154 -0.000157 -0.00016 -0.000171 -0.000185 -0.000212
-0.000238 -0.000256 -0.000259 -0.000263 -0.000273 ... C

> returns2[1:10,1]
 [1] -0.002206  0.115696 -0.015192  0.008719 -0.004654 -0.010688  0.009453
0.002676  0.001334 -0.011326

> as.numeric(returns[2528:2537,1])
 [1]  341 7444 2244 5149  787 1717 5251 4122 3878 1811

> as.numeric(returns2[1:10,1])
 [1] -0.002206  0.115696 -0.015192  0.008719 -0.004654 -0.010688  0.009453
0.002676  0.001334 -0.011326

I would like to understand what's happening and how to handle the longer
one. This problem may seem stupid, but I've been trying to figure it out for
a while and nothing seems to work. I checked in excel and both seems to be
completely normal lists of real numbers).

What am I missing here? What are those "levels" and why the as.numeric
doesn't work the same with the longer one?

My final goal  is to extract small parts of those columns the following way:

> cbind(returns[which(names == id)[2528:2537],1])
      [,1]
 [1,]  341
 [2,] 7444
 [3,] 2244
 [4,] 5149
 [5,]  787
 [6,] 1717
 [7,] 5251
 [8,] 4122
 [9,] 3878
[10,] 1811

Wich should be equivalent to:

> cbind(returns2[which(names == id)[1:10],1])
           [,1]
 [1,] -0.002206
 [2,]  0.115696
 [3,] -0.015192
 [4,]  0.008719
 [5,] -0.004654
 [6,] -0.010688
 [7,]  0.009453
 [8,]  0.002676
 [9,]  0.001334
[10,] -0.011326

Thanks a lot,
Thibault

---------
*Thibault Vatter*
 EPFL- Master, 1ère année
Laboratory of Statistical Biophysics <http://lbs.epfl.ch/>

Tel: +41 78 820 18 64
 @: thibault.vatter@epfl.ch
Web: http://personnes.epfl.ch/thibault.vatter

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