[R] indexing question
Leeds, Mark (IED)
Mark.Leeds at morganstanley.com
Mon Nov 13 21:28:53 CET 2006
thanks beilton but that won't work. A diff will also include 61-41 etc
and I don't want to include those.
I'm working on using lapply or sapply with a seq along 31, 61, etc.
I'll let you know if it works.
-----Original Message-----
From: Benilton Carvalho [mailto:bcarvalh at jhsph.edu]
Sent: Monday, November 13, 2006 3:18 PM
To: Leeds, Mark (IED)
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] indexing question
diff(tmp[idx])
cheers,
b
On Nov 13, 2006, at 3:06 PM, Leeds, Mark ((IED)) wrote:
> I have the following set of indices, call it idx, that correspond to
> the indices of a vector say temp.
>
> [1] 31 36 41 61 66 71 91 96 101 121 126 131 151
> 156 161 181 186 191 211 216 221 241 246 251 271 276 281
> 301 306 311 331 336 341 361 366 [36] 371 391 396 401 421
> 426 431 451 456 461 481 486 491
> 511 516 521 541 546 551 571 576 581 601 606 611 631 636
> 641 661 666 671 691 696 701 721 [71] 726 731 751 756 761
> 781 786 791 811 816 821 841 846
> 851 871 876 881 901 906 911 931 936 941 961 966 971 991
> 996 1001 1021 1026 1031 1051 1056 1061 [106] 1081 1086 1091 1111 1116
> 1121 1141 1146 1151 1171 1176 1181 1201
> 1206 1211 1231 1236 1241 1261 1266 1271 1291 1296 1301 1321 1326 1331
> 1351 1356 1361 1381 1386 1391 1411 1416 [141] 1421
>
>
> I want to calculate temp[36] - temp[31] and temp[41] - temp[36]
>
> Similarly, temp[66] - temp[61] and temp[71] - temp[66] .
> .
> .
> .
> Similarly temp[1416]-temp[1411]
> temp[1421] - temp[1416]
>
>
> I'm doing this because the above subractions represent pairs of
> returns
> and the correlations between them wil be calculated eventually.
>
> In other words, eventually I will have
>
> X_36_31 ( i.e : temp[36] - temp[31] )
> X_66-61
> X_96-91
> .
> .
> .
> .
> .
> .
> .
> X_1411-1416
>
> as one vector and
>
> Y_41-36
> Y_71-66
> Y_101-96
> .
> .
> .
> .
> .
> Y_1416_1421
>
> as another vector.
>
> and will calculate the correlation between the two vectors in order to
> get one number.
>
>
> The point is I am really only using the indices 31, 61, 91 etc as
> anchor's so a regular diff(temp[idx]) won't work because it will diff
> all
> the elements that are next to each other ? This is a weird problem.
> I'm
> still thinking about it. I'm hoping to figure it out before someone
> sends me something but I won't mind so much if I get an external
> solution first. I have no pride.
> --------------------------------------------------------
>
> This is not an offer (or solicitation of an offer) to buy/se...
> {{dropped}}
>
> ______________________________________________
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--------------------------------------------------------
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