Re: [R] Help with merge function

[Rui Barradas]

Hello,

I don't understand the question, what range? I've just changed the 'all' 
argument to 'all.y', without doing anything special to the variables.
Can you explain what you mean?
Rui Barradas


Em 26-04-2013 19:30, Catarina Ferreira escreveu:
Hello, Thank you for your help. However the dataframes I gave you were only
examples, the actual dataframes are very big. Does this mean I have to
write every range of data for each variable??


On Fri, Apr 26, 2013 at 2:25 PM, Rui Barradas <ruipbarra...@sapo.pt> wrote:

Hello,

The following seems to do the trick.



x1 <-
structure(list(State_prov = c("Nova Scotia", "Nova Scotia", "Nova Scotia"
), Shape_name = c("Annapolis", "Antigonish", "Gly"), bob2009 = c(0L,
0L, NA), bob2010 = c(0L, 0L, NA), bob2011 = c(1L, 0L, NA)), .Names =
c("State_prov",
"Shape_name", "bob2009", "bob2010", "bob2011"), class = "data.frame",
row.names = c(NA,
-3L))

x2 <-
structure(list(FID = 0:2, State_prov = c("Nova Scotia", "Nova Scotia",
"Nova Scotia"), Shape_name = c("Annapolis", "Antigonish", "Gly"
), bob2009 = c(0L, 0L, 0L), bob2010 = c(0L, 0L, 0L), coy2009 = c(10L,
1L, 1L)), .Names = c("FID", "State_prov", "Shape_name", "bob2009",
"bob2010", "coy2009"), class = "data.frame", row.names = c(NA,
-3L))

x3  <- merge(x1, x2, all.y = TRUE)



Note also that since by = intersect(names(x1), names(x2)), you really
don't need it, it's the default behavior.

Hope this helps,

Rui Barradas

Em 26-04-2013 18:10, Catarina Ferreira escreveu:

  Dear all,

I'm trying to merge 2 dataframes, but I'm not being entirely successful
and
I can't understand why.

Dataframe x1

State_prov     Shape_name   bob2009   bob 2010   bob2011
Nova Scotia    Annapolis         0                  0              1
Nova Scotia    Antigonish        0                  0              0
Nova Scotia    Gly                   NA               NA             NA

Dataframe x2 - has 20000 rows and 193 variables, contains one important
field which is "FID" that is a link to a shapefile (this is not in x1) and
shares common columns with x1, like this:

FID     State_prov     Shape_name   bob2009   bob 2010  coy 2009
   0        Nova Scotia    Annapolis         0
0              10
   1        Nova Scotia    Antigonish        0
0              1
   2        Nova Scotia    Gly                   0
0              1

So when I do

x3  <- merge(x1, x2, by=intersect(names(x1), names(x2)), all=TRUE)

it should do the trick. The thing is that it works for the columns (it
adds
all the new columns not common to both dataframes), but it also adds the
rows. This is what I get (x3):

FID     State_prov     Shape_name   bob2009   bob 2010  coy 2009   bob2011
   0        Nova Scotia    Annapolis         0
0              10            NA
   NA      Nova Scotia    Annapolis         NA               NA          NA
              1
   1        Nova Scotia    Antigonish        0
0              1               NA
NA      Nova Scotia    Antigonish        NA               NA          NA
              0
   2        Nova Scotia    Gly                   0
0              1               NA
NA      Nova Scotia    Gly                   NA               NA
NA             NA

What I want to get is a true merge, like this:

FID     State_prov     Shape_name   bob2009   bob 2010  coy 2009   bob2011
   0        Nova Scotia    Annapolis         0
0              10            1
   1        Nova Scotia    Antigonish        0
0              1               0
   2        Nova Scotia    Gly                   0
0              1               NA

Can anybody please help me to understand what I'm doing wrong.
Any help will be much appreciated!!






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