[R] writing function

[arnaud Gaboury]

Thank you so much. You are totally right.




> -----Original Message-----
> From: Joshua Wiley [mailto:jwiley.psych at gmail.com]
> Sent: Monday, May 24, 2010 6:33 PM
> To: arnaud Gaboury
> Cc: r-help at r-project.org
> Subject: Re: [R] writing function
> 
> My guess is that either ls(), called inside grep() or mget() is
> looking in an environment you do not want it to.  When you create a
> function, it has it's own environment.  If you want the dataframes to
> be created inside the function call (which is what I think you were
> doing before), you should set ls() and mget() to use your function
> environment.  If the dataframes are supposed to be in the global
> environment, I would try adding:
> 
> mget(grep("DailyPL",ls(envir=.GlobalEnv),value=TRUE),envir=.GlobalEnv))
> 
> HTH,
> 
> Josh
> 
> On Mon, May 24, 2010 at 9:17 AM, arnaud Gaboury
> <arnaud.gaboury at gmail.com> wrote:
> > Dear group,
> >
> > Here is my environment after I run a function, myfun()
> >
> >>myfun()
> >> ls()
> >  [1] "allcon"        "avprix16"      "DailyPL100416" "DailyPL100419"
> > "DailyPL100420" "l"             "ll"            "myl"           "PL"
> > "PLdaily"       "PLglobal"      "PLmonthly"
> > [13] "Pos100415"     "Pos100416"     "Pos100419"     "Pos100420"
> > "pose15"        "pose16"        "position"      "r"
> "result"
> > "sel"           "select"        "Trad100415"
> > [25] "Trad100416"    "Trad100419"    "Trad100420"    "trade"
> "tt"
> > "value"         "w"             "zz"
> >
> > Elements "DailyPL100416" "DailyPL100419" "DailyPL100420" are data
> frames
> > created by a function, myfun().
> > If then I pass this line manually at the prompt:
> >
> >>dd<-data.frame(do.call(rbind,
> >
> mget(grep("DailyPL",ls(),value=TRUE),envir=.GlobalEnv)),row.names=NULL)
> >
> > Here is what I get, wich is the expected result :
> >
> > dd <-
> > structure(list(DESCRIPTION = structure(c(2L, 5L, 6L, 7L, 9L,
> > 11L, 12L, 15L, 14L, 16L, 1L, 10L, 3L, 4L, 13L, 8L, 17L, 2L, 3L,
> > 5L, 7L, 9L, 11L, 12L, 13L, 14L, 16L, 18L, 8L, 6L, 10L, 15L, 5L,
> > 19L, 9L, 10L, 11L, 12L, 13L, 14L, 16L, 2L, 3L, 20L, 18L, 7L,
> > 21L), .Label = c("COFFEE C Jul/10", "COPPER May/10", "CORN Jul/10",
> > "CORN May/10", "COTTON NO.2 Jul/10", "CRUDE OIL miNY May/10",
> > "GOLD Jun/10", "HENRY HUB NATURAL GAS May/10", "ROBUSTA COFFEE (10)
> Jul/10",
> >
> > "SILVER May/10", "SOYBEANS Jul/10", "SPCL HIGH GRADE ZINC USD",
> > "STANDARD LEAD USD", "SUGAR NO.11 Jul/10", "SUGAR NO.11 May/10",
> > "WHEAT Jul/10", "WHEAT May/10", "CRUDE OIL miNY Jun/10", "HENRY HUB
> NATURAL
> > GAS Jun/10",
> > "PALLADIUM Jun/10", "PLATINUM Jul/10"), class = "factor"), PL =
> c(3500,
> > -1874.99999999999, -2612.50000000003, -2169.99999999998, -680,
> > 425, 1025, 1008.00000000000, -3057.59999999999, 3212.5, -
> 1781.25000000001,
> > -2265.0, 75, -387.5, 2950, 490.000000000013, 0, 2612.49999999998,
> > -4162.5, 279.99999999998, 589.999999999964, -3670, -1212.5, 887.5,
> > -625, 3976.00000000000, -7250, -1112.50000000000, -289.999999999999,
> > -1414.99999999999, 275, -526.400000000003, 6914.99999999999,
> > -19.9999999999978, -2330, 54.9999999999955, 1725, -3012.5, -5175,
> > -1769.60000000001, 3787.5, -537.500000000009, 175, -5330.00000000001,
> > 362.49999999999, 590.000000000009, -2995.00000000000)), .Names =
> > c("DESCRIPTION",
> > "PL"), row.names = c(NA, -47L), class = "data.frame")
> >
> > If I add this same line at the end of my function , here is what I
> get:
> >
> >> myfun()
> > data frame with 0 columns and 0 rows  #dd doesn't return
> >
> >
> > What is wrong?
> >
> > Thank you for help.
> >
> > ______________________________________________
> > R-help at 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.
> >
> 
> 
> 
> --
> Joshua Wiley
> Senior in Psychology
> University of California, Riverside
> http://www.joshuawiley.com/