Re: [R] merge multiple data frames

Massimo Bressan Mon, 30 Jan 2012 07:13:58 -0800

thanks michael

it's working like a charm: that's exaclty what I was looking for


bye

max

----- Original Message -----From: "R. Michael Weylandt" <michael.weyla...@gmail.com>

To: "Massimo Bressan" <mbres...@arpa.veneto.it>
Cc: <r-help@r-project.org>
Sent: Friday, January 27, 2012 4:16 PM
Subject: Re: [R] merge multiple data frames


Oh, sorry -- I assumed that was intentional since my code passed the
identical() test with what you said you wanted.

Perhaps this gets what you meant you wanted instead (though the
treatment of the names is far from elegant)

mergeAll <- function(..., by = "date", all = TRUE) {
 dotArgs <- list(...)
 dotNames <- lapply(dotArgs, names)
 repNames <- Reduce(intersect, dotNames)
 repNames <- repNames[repNames != by]
 for(i in seq_along(dotArgs)){
   wn <- which( (names(dotArgs[[i]]) %in% repNames) &
(names(dotArgs[[i]]) != by))
   names(dotArgs[[i]])[wn] <- paste(names(dotArgs[[i]])[wn],
                                    names(dotArgs)[[i]], sep = ".")
 }
 Reduce(function(x, y) merge(x, y, by = by, all = all), dotArgs)
}

print(str(mergeAll(a=a,b=b,c=c)))

Is that what you were going for?

Michael

On Fri, Jan 27, 2012 at 3:19 AM, Massimo Bressan
<mbres...@arpa.veneto.it> wrote:

I tested your code: it's OK but there is still the problem of the suffixes
for the last dataframe....
thank you for the support

----- Original Message ----- From: "R. Michael Weylandt"
<michael.weyla...@gmail.com>
To: "maxbre" <mbres...@arpa.veneto.it>
Cc: <r-help@r-project.org>
Sent: Thursday, January 26, 2012 8:19 PM
Subject: Re: [R] merge multiple data frames

I might do something like this:

mergeAll <- function(..., by = "date", all = TRUE) {
dotArgs <- list(...)
Reduce(function(x, y)
merge(x, y, by = by, all = all, suffixes=paste(".", names(dotArgs),
sep = "")),
dotArgs)}

mergeAll(a = a, b = b, c = c)

str(.Last.value)

You also might be able to set it up to capture names without you
having to put "a = a" etc. using substitute.

On Thu, Jan 26, 2012 at 12:29 PM, maxbre <mbres...@arpa.veneto.it> wrote:


This is my reproducible example (three data frames: a, b, c)

a<-structure(list(date = structure(1:6, .Label = c("2012-01-03",
"2012-01-04", "2012-01-05", "2012-01-06", "2012-01-07", "2012-01-08",
"2012-01-09", "2012-01-10", "2012-01-11", "2012-01-12", "2012-01-13",
"2012-01-14", "2012-01-15", "2012-01-16", "2012-01-17", "2012-01-18",
"2012-01-19", "2012-01-20", "2012-01-21", "2012-01-22", "2012-01-23"

), class = "factor"), so2 = c(0.799401398190476, 0, 0,0.0100453950434783,

0.200154920565217, 0.473866969181818), nox = c(111.716109973913,
178.077239330435, 191.257829021739, 50.6799951473913, 115.284643540435,
110.425185027727), no = c(48.8543691516522, 88.7197448817391,
93.9931932472609, 13.9759949817391, 43.1395266865217, 41.7280296016364
), no2 = c(36.8673432865217, 42.37150668, 47.53311701, 29.3026882474783,
49.2986070321739, 46.5978461731818), co = c(0.618856168125,
0.996593475083333,
0.666987416083333, 0.383437311166667, 0.281604928875, 0.155383408913043
), o3 = c(12.1393100029167, 12.3522739816522, 10.9908791203043,
26.9122200013043, 13.8421695947826, 12.3788847045455), ipa =
c(167.541954974667,
252.7196257875, 231.802370709167, 83.4850259595833, 174.394613581667,
173.868599272609), ws = c(1.47191016429167, 0.765781205208333,
0.937053086791667, 1.581022406625, 0.909756802125, 0.959252831695652
), wd = c(45.2650019737732, 28.2493544114369, 171.049080544214,
319.753674830936, 33.8713897347193, 228.368119533759), temp =
c(7.91972825883333,
3.79434291520833, 2.1287644735, 6.733854600625, 3.136579722,
3.09864120704348), umr = c(86.11566638875, 94.5034087491667,
94.14451249375, 53.1016709004167, 65.63420423, 74.955669236087
)), .Names = c("date", "so2", "nox", "no", "no2", "co", "o3",
"ipa", "ws", "wd", "temp", "umr"), row.names = c(NA, 6L), class =
"data.frame")


b<-structure(list(date = structure(1:6, .Label = c("2012-01-03",
"2012-01-04", "2012-01-05", "2012-01-06", "2012-01-07", "2012-01-08",
"2012-01-09", "2012-01-10", "2012-01-11", "2012-01-12", "2012-01-13",
"2012-01-14", "2012-01-15", "2012-01-16", "2012-01-17", "2012-01-18",
"2012-01-19", "2012-01-20", "2012-01-21", "2012-01-22", "2012-01-23"
), class = "factor"), so2 = c(0, 0, 0, 0, 0, 0), nox = c(13.74758511,
105.8060582, 61.22720599, 11.45280354, 56.86804174, 39.17917222
), no = c(0.882593766, 48.97037506, 9.732937217, 1.794549972,
16.32300019, 8.883637786), no2 = c(11.80447753, 25.35235381,
28.72990261, 8.590004034, 31.9003796, 25.50512403), co = c(0.113954917,
0.305985964, 0.064001839, 0, 1.86e-05, 0), o3 = c(5.570499897,
9.802379608, 5.729360104, 11.91304016, 12.13407993, 10.00961971
), ipa = c(6.065110207, 116.9079971, 93.21240234, 10.5777998,
66.40740204, 34.47359848), ws = c(0.122115001, 0.367668003, 0.494913995,
0.627124012, 0.473895013, 0.593913019), wd = c(238.485119317031,
221.645073036776, 220.372076815032, 237.868340917096, 209.532933617465,
215.752030286564), temp = c(4.044159889, 1.176810026, 0.142934993,
0.184606999, -0.935989976, -2.015399933), umr = c(72.29229736,
88.69879913, 87.49530029, 24.00079918, 44.8852005, 49.47729874
)), .Names = c("date", "so2", "nox", "no", "no2", "co", "o3",
"ipa", "ws", "wd", "temp", "umr"), row.names = c(NA, 6L), class =
"data.frame")


c<-structure(list(date = structure(1:6, .Label = c("2012-01-03",
"2012-01-04", "2012-01-05", "2012-01-06", "2012-01-07", "2012-01-08",
"2012-01-09", "2012-01-10", "2012-01-11", "2012-01-12", "2012-01-13",
"2012-01-14", "2012-01-15", "2012-01-16", "2012-01-17", "2012-01-18",
"2012-01-19", "2012-01-20", "2012-01-21", "2012-01-22", "2012-01-23"
), class = "factor"), so2 = c(2.617839247, 0, 0, 0.231044086,
0.944608887, 2.12400444), nox = c(308.9046313, 275.6778849, 390.0824142,
178.7429364, 238.655832, 251.892601), no = c(156.0262489, 151.4412498,
221.0725021, 65.96049786, 106.541748, 119.3471241), no2 = c(74.80145447,
59.29991481, 66.5897975, 77.84267978, 75.68422569, 85.43044816
), co = c(1.628431197, 1.716231492, 1.264678366, 1.693460745,
0.780637084, 0.892724398), o3 = c(26.1473999, 15.91584015, 22.46199989,
37.39400101, 15.63426018, 17.51494026), ipa = c(538.414978, 406.4620056,
432.6459961, 275.2820129, 435.7909851, 436.8039856), ws = c(4.995530128,
1.355309963, 1.708899975, 3.131690025, 1.546270013, 1.571320057
), wd = c(58.15639877, 64.5657153143848, 39.9754269501381,
24.0739884380921,
55.9453098437477, 56.7648829092446), temp = c(10.24740028, 7.052690029,
4.33258009, 13.91609955, 8.762220383, 11.04300022), umr = c(97.60900116,
96.91899872, 96.20649719, 94.74620056, 82.04550171, 89.41320038
)), .Names = c("date", "so2", "nox", "no", "no2", "co", "o3",
"ipa", "ws", "wd", "temp", "umr"), row.names = c(NA, 6L), class =
"data.frame")


Given the three data frames “a”, “b” and “c”, I need to merge them all by
the common field “date”.
The following attempt is working fine but…

# code start
all<-merge(a,b,by="date",suffixes=c(".a",".b"),all=T)
all<-merge(all,c,by="date",all=T)
# code end

…I would like to possibly do it in just “one shot” (a generalisation of
the
code for a more complex case of handling many data frames) also by
assigning
proper suffixes to each variable (not possible with the previous code
snippet)

Then I also try a different approach with the use of the library reshape
and
the function “merge_all” but…

# code start
library("reshape")
all.new<-merge_all(a, b, c, by="date", all=T, suffixes=c(".a",".b",".c"))
# code end

…I got the following error message:
error in merge in merge.data.frame(as.data.frame(x), as.data.frame(y),
...)
:
formal argument "all" associated to different argument passed
(a free translation from italian)

My question is:
how to accomplish the merging of multiple data frames with all the same
variable names and by a single id field with the need of “keeping track”
of
the original data frame by means of the use of suffixes appended to new
variables?

Any help much appreciated

Thank you




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Re: [R] merge multiple data frames

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