Merging multiple data frames on two common columns

Question

Merging multiple data frames on two common columns

I saw several questions about merging csv files into one data frame. What to do if data frames are already in the workspace. I have five wide zoos that I drop as data frames and then melt away. Here is the chapter of one:

> head(df.mon.ssf.ret)
      date variable value
1 2009.000     AA1C    NA
2 2009.083     AA1C    NA
3 2009.167     AA1C    NA
4 2009.250     AA1C    NA
5 2009.333     AA1C    NA
6 2009.417     AA1C    NA

I could combine them in a "date" and a "variable" with a series of nested merges, but that seems awkward. Is there a more programmatic way to merge?

If I am sure that the columns are in the same order in all zoos, can I be sure that the melt maintains this order and uses it cbind? Thank!

Update:

- . , , :

> temp <- merge(z.ssf.oi, z.ssf.oig, z.ssf.ret)
> class(temp)
[1] "zoo"
> temp2 <- cbind(index(temp), as.data.frame(temp))
> class(temp2)
[1] "data.frame"
> names(temp2)[1] <- "date"
> dim(temp2)
[1]   12 1204
> temp3 <- melt(temp2, id="date")
Error in data.frame(ids, variable, value) : 
  arguments imply differing number of rows: 12, 14436
> head(temp2)[, 1:5]
             date AA1C.z.ssf.oi AAPL1C.z.ssf.oi ABT1C.z.ssf.oi ABX1C.z.ssf.oi
Jan 2009 Jan 2009      1895.800        49191.25             NA             NA
Feb 2009 Feb 2009      1415.579        42650.26             NA        6267.96
Mar 2009 Mar 2009      1501.398        36712.20             NA       11581.65
Apr 2009 Apr 2009      1752.936        74376.27             NA       12168.29
May 2009 May 2009      1942.874        96307.30             NA       13490.60
Jun 2009 Jun 2009            NA        79170.70             NA       16337.21

2: !

> A <- cbind(index(z.ssf.oi), as.data.frame(z.ssf.oi))
> names(A)[1] <- "date"
> B <- cbind(index(z.ssf.oig), as.data.frame(z.ssf.oig))
> names(B)[1] <- "date"
> C <- cbind(index(z.ssf.ret), as.data.frame(z.ssf.ret))
> names(C)[1] <- "date"
> A.melt <- melt(A, id="date")
> head(A.melt)
      date variable value
1 Jan 2009      A1C    NA
2 Feb 2009      A1C    NA
3 Mar 2009      A1C    NA
4 Apr 2009      A1C    NA
5 May 2009      A1C    NA
6 Jun 2009      A1C    NA
> B.melt <- melt(B, id="date")
> C.melt <- melt(C, id="date")
> ans <- merge(merge(A.melt, B.melt, by=c("date", "variable")), C.melt, by=c("date", "variable"))
> names(ans)[3:5] <- c("oi", "oig", "ret")
> head(ans)
      date variable       oi       oig         ret
1 Apr 2009      A1C       NA        NA          NA
2 Apr 2009     AA1C       NA        NA          NA
3 Apr 2009   AAPL1C 59316.88 0.3375786 0.008600073
4 Apr 2009    ABB1C       NA        NA          NA
5 Apr 2009    ABT1C       NA        NA          NA
6 Apr 2009    ABX1C       NA        NA          NA

( NA - )

3: dputs ( [1:10, 1:10] )

> dput(A)
structure(list(group = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L), class = "factor", .Label = "oi"), date = structure(c(2009, 
2009.08333333333, 2009.16666666667, 2009.25, 2009.33333333333, 
2009.41666666667, 2009.5, 2009.58333333333, 2009.66666666667, 
2009.75), class = "yearmon"), AA1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), AAPL1C = c(49226.391, 42662.1589473684, 35354.4254545455, 
57161.6495238095, 84362.895, NA, NA, 47011.8519047619, 57852.2171428571, 
33058.0090909091), ABT1C = c(NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), 
    ABX1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ACE1C = c(NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_), ACI1C = c(NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_), ACS1C = c(NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_), ADBE1C = c(NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
    ), ADCT1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ADI1C = c(NA_real_, 
    NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
    NA_real_, NA_real_, NA_real_)), .Names = c("group", "date", 
"AA1C", "AAPL1C", "ABT1C", "ABX1C", "ACE1C", "ACI1C", "ACS1C", 
"ADBE1C", "ADCT1C", "ADI1C"), row.names = c("Jan 2009", "Feb 2009", 
"Mar 2009", "Apr 2009", "May 2009", "Jun 2009", "Jul 2009", "Aug 2009", 
"Sep 2009", "Oct 2009"), class = "data.frame")
> dput(B)
structure(list(group = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L), class = "factor", .Label = "oig"), date = structure(c(2009.08333333333, 
2009.16666666667, 2009.25, 2009.33333333333, 2009.41666666667, 
2009.5, 2009.58333333333, 2009.66666666667, 2009.75, 2009.83333333333
), class = "yearmon"), AA1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), AAPL1C = c(-0.143117562125788, -0.187888745830302, 0.480459636485712, 
0.389244461579155, NA, NA, NA, 0.207492040517069, -0.559627909130612, 
NA), ABT1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ABX1C = c(NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_), ACE1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), ACI1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ACS1C = c(NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_), ADBE1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), ADCT1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ADI1C = c(NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_)), .Names = c("group", "date", "AA1C", "AAPL1C", 
"ABT1C", "ABX1C", "ACE1C", "ACI1C", "ACS1C", "ADBE1C", "ADCT1C", 
"ADI1C"), row.names = c("Feb 2009", "Mar 2009", "Apr 2009", "May 2009", 
"Jun 2009", "Jul 2009", "Aug 2009", "Sep 2009", "Oct 2009", "Nov 2009"
), class = "data.frame")
> dput(C)
structure(list(group = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 1L), class = "factor", .Label = "ret"), date = structure(c(2009, 
2009.08333333333, 2009.16666666667, 2009.25, 2009.33333333333, 
2009.41666666667, 2009.5, 2009.58333333333, 2009.66666666667, 
2009.75), class = "yearmon"), AA1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), AAPL1C = c(-0.143117562125788, -0.187888745830302, 0.480459636485712, 
0.389244461579155, NA, NA, NA, 0.207492040517069, -0.559627909130612, 
NA), ABT1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ABX1C = c(NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_), ACE1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), ACI1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ACS1C = c(NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_), ADBE1C = c(NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_
), ADCT1C = c(NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_), ADI1C = c(NA_real_, 
NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, NA_real_, 
NA_real_, NA_real_)), .Names = c("group", "date", "AA1C", "AAPL1C", 
"ABT1C", "ABX1C", "ACE1C", "ACI1C", "ACS1C", "ADBE1C", "ADCT1C", 
"ADI1C"), row.names = c("Feb 2009", "Mar 2009", "Apr 2009", "May 2009", 
"Jun 2009", "Jul 2009", "Aug 2009", "Sep 2009", "Oct 2009", "Nov 2009"
), class = "data.frame")

+5

merge r reshape melt

Richard Herron 16 . '10 22:40

1

Thierry · Accepted Answer · 2010-11-17T10:59:38+0000

. , . z.sfff.oi, z.sff.oig z.sff.ret, . dput() .

A <- data.frame(Group = "oi", date = as.factor(index(z.ssf.oi),) as.data.frame(z.ssf.oi)))
B <- data.frame(Group = "oig", date = as.factor(index(z.ssf.oig)), as.data.frame(z.ssf.oig)))
C <- data.frame(Group = "ret", date = as.factor(index(z.ssf.ret)), as.data.frame(z.ssf.ret)))
Long <- melt(rbind(A, B, C), id.vars = c("Group", "date")))
cast(date ~ Group, data = Long)

Merging multiple data frames on two common columns

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