Hi, I cannot make a reproducible example easily for my problem, so I'll describe it as best as I can.
I merged 2 dataframes but was surprised when one line on the x dataframe did not get a match in the y dataframe, because I knew such a match existed. There was only one "by" variable in the merge, in Date format: in x: $ période : Date, format: "2009-06-09" "2009-07-09" ... in y: $ date : Date, format: "2009-05-12" "2009-06-09" … I extracted the date that did not match into variables a (from x) and b (from y): > a=test1$période[21] > b=test2$date[22] > a [1] "2011-04-06" > b [1] "2011-04-06" and then this very puzzling situation: a==b [1] FALSE > as.integer(a) [1] 15070 > as.integer(b) [1] 15070 > as.integer(a)==as.integer(b) [1] TRUE Thanks in advance for an explanation or a suggestion to further study this puzzle, Denis sessionInfo() R version 2.15.0 (2012-03-30) Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit) locale: [1] fr_CA.UTF-8/en_US.UTF-8/fr_CA.UTF-8/C/fr_CA.UTF-8/fr_CA.UTF-8 attached base packages: [1] splines stats graphics grDevices utils datasets methods [8] base other attached packages: [1] doBy_4.5.2 MASS_7.3-17 snow_0.3-8 lme4_0.999375-42 [5] Matrix_1.0-6 lattice_0.20-6 multcomp_1.2-12 mvtnorm_0.9-9992 [9] R2HTML_2.2 survival_2.36-12 gdata_2.8.2 loaded via a namespace (and not attached): [1] grid_2.15.0 gtools_2.6.2 nlme_3.1-103 stats4_2.15.0 tools_2.15.0 ______________________________________________ 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.
