Note: even if I say by=c("LON", "LAT"), it doesn't work, suggesting that
number storage isn't the problem

On Wed, Aug 26, 2009 at 6:19 PM, Mehdi Khan <mwkhan@ucdavis.edu> wrote:

> Hello everyone,
>
> Merging two dataframes should be easy.  However when I try to merge, R
> doesn't recognize identical values, even if I am doing it by values that
> have no decimals.
>
> willclayong:
>    vs30      LON     LAT  Net  X wills.cat wills.vs30 clahan.cat clahanvs30
> PolyID.wills PolyID.clahan tif.cat STA ELEVATION tif.vs30
> 1 338.539 -3849590 4319319 <NA>  2         D        301          D
> 377         1958          1942       1 150        NA      519
> 2 712.822 -3849590 4319319 <NA>  3         D        301          D
> 377         1958          1942       1 479        NA      519
> 3 477.652 -3836584 4288164 <NA> 10         C        464          C
> 489         1194          9353       3 148        NA      547
> 4 513.703 -3836575 4287739 <NA> 11         C        464          C
> 489         1194          9353       3 485        NA      547
> 5 477.652 -3835886 4289120 <NA> 12         C        464          C
> 489         1194          9353       7 147        NA      388
>
> wald:
>
> > wald_ol_sta[1:10,]
>     X Wald.vs30  STA    vs30      LON     LAT
> 1   1   434.417 1502 274.500 -3077929 3759564
> 2   2   378.049 NEE2 363.000 -3086165 3718184
> 3   3   196.848  EMS 336.000 -3143337 3500449
> 4   4   557.625 1498 659.600 -3103738 3871531
> 5   5   263.878 1497 274.500 -3102944 3878068
> 6   6   374.898 1499 274.500 -3109753 3858460
> 7   7   150.000  230 274.500 -3154048 3482703
> 8   8   248.342 1205 207.469 -3153294 3497116
> 9   9   422.256 1495 338.600 -3097854 3990339
> 10 10   322.540 1496 274.500 -3115300 3863905
>
> willsclayongwald<-merge(wald_ol_sta, willsclayong, by=c("LON", "LAT",
> "STA", "vs30"))
>
> returns nothing... if I modify the previous script by adding "all=TRUE", I
> get this:
>
>
> lsclayongwald[1:10,]
>         LON     LAT STA    vs30  X.x       Wald.vs30  Net X.y wills.cat
> wills.vs30 clahan.cat clahanvs30 PolyID.wills PolyID.clahan tif.cat
> ELEVATION tif.vs30
> 1  -3854850 4321856 478  513.703 1155       586.685 <NA>  NA
> <NA>         NA       <NA>         NA           NA            NA
> NA        NA       NA
> 2  -3849590 4319319 150  338.539   NA         NA <NA>   2         D
> 301          D        377         1958          1942       1        NA
> 519
> 3  -3849590 4319319 479  712.822   NA         NA <NA>   3         D
> 301          D        377         1958          1942       1        NA
> 519
> 4  -3849590 4319319 150  338.539 1152       336.794 <NA>  NA
> <NA>         NA       <NA>         NA           NA            NA
> NA        NA       NA
>
>
> rows 2 and 4 should have merged.  Why didn't they?
>
>
> thanks!
>
>
> Mehdi Khan
>
>

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