[R] a little problem on selecting a subset from dataset A accordingto dataset B?

[jim holtman]

You might want to be careful since what you are comparing is floating
point numbers.  You might want to scale them and then convert to
integers to make sure that you are getting the numbers you think you
should be getting. (FAQ 7.31)

On 7/9/07, Bill.Venables at csiro.au <Bill.Venables at csiro.au> wrote:
> > AB <- with(B, subset(A, coords.x1 %in% X1))
> > AB
>   coords.x1 coords.x2
> 0   542250.9   3392404
> 7   541512.5   3394722
> 8   541479.3   3394878
> 9   538903.4   3395943
> 18  543274.0   3389919
> 19  543840.8   3392012
>
>
>
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of zhijie zhang
> Sent: Monday, 9 July 2007 2:43 AM
> To: R-help at stat.math.ethz.ch
> Subject: [R] a little problem on selecting a subset from dataset A
> accordingto dataset B?
>
> Dear Friends,
>   I want to extract the records from A according to B, but the results
> are
> not correct because R says :
>  The length of long object is not integer times on the length of short
> object.
>  Anybody have met the same problem? How to do it correctly?
>
> length(A)=47
> length(B)=6
>
> A[A$coords.x1==B$X1,]   #the program for the above task. I should get 6
> records, but i only get former 4 records for the above reason.
>
> Thanks.
>  The folloing shows dataset A and B.
>
>
> > A
>   coords.x1 coords.x2
> 0  542250.89 3392404.1
> 1  538813.87 3388339.0
> 2  536049.19 3385821.6
> 3  533659.62 3383194.2
> 4  530642.30 3376834.9
> 5  529573.15 3378177.8
> 6  530853.82 3394838.8
> 7  541512.51 3394721.6
> 8  541479.33 3394877.8
> 9  538903.39 3395942.5
> 10 536019.95 3396286.1
> 11 538675.23 3384213.2
> 12 535127.95 3381255.4
> 13 533852.24 3378660.4
> 14 531360.91 3379273.8
> 15 539289.14 3375759.8
> 16 543410.51 3384353.1
> 17 543089.27 3388170.1
> 18 543274.03 3389919.2
> 19 543840.77 3392012.4
> 20 553383.55 3402401.8
> 21 554621.51 3397938.9
> 22 564096.42 3397524.4
> 23 567529.64 3398702.9
> 24 561798.76 3404864.0
> 25 562868.34 3405502.2
> 26 563145.22 3403192.1
> 27 562419.87 3404090.4
> 28 558321.85 3403879.9
> 29 567050.74 3404973.1
> 30 570609.70 3408742.4
> 31 556777.57 3397858.0
> 32 531353.38 3368596.6
> 33 533513.50 3372749.3
> 34 537543.19 3364284.8
> 35 538779.41 3368224.8
> 36 525930.09 3374067.7
> 37 522990.85 3369213.1
> 38 528826.37 3359019.0
> 39 533865.85 3362595.4
> 40 531200.25 3365053.0
> 41 551054.10 3377181.3
> 42 546974.19 3369284.8
> 43 572315.59 3359541.1
> 44 562703.63 3355173.4
> 45 558959.31 3357804.4
> 46 558531.39 3361741.1
>
>
> > B
>         X1        X2
> 1 542250.89 3392404.1
> 2 541512.51 3394721.6
> 3 541479.33 3394877.8
> 4 538903.39 3395942.5
> 5 543274.03 3389919.2
> 6 543840.77 3392012.4
>
> --
> With Kind Regards,
>
> oooO:::::::::
> (..):::::::::
> :\.(:::Oooo::
> ::\_)::(..)::
> :::::::)./:::
> ::::::(_/::::
> :::::::::::::
> [***********************************************************************
> ]
> Zhi Jie,Zhang ,PHD
> Tel:86-21-54237149
> Dept. of Epidemiology,School of Public Health,Fudan University
> Address:No. 138 Yi Xue Yuan Road,Shanghai,China
> Postcode:200032
> Email:epistat at gmail.com
> Website: www.statABC.com
> [***********************************************************************
> ]
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?