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 -- View this message in context: http://r.789695.n4.nabble.com/merge-multiple-data-frames-tp4331089p4331089.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.