[R] Spread data.frame on 2 variables

[Ulrik Stervbo]

Hi Georg,

it's hard to tell without a reproducible example.

Should spread really merge elements? Does spread know anything about
CustID? Maybe you need to make a useful key of the CustIDs first and spread
on that?

Maybe I'm all off, because I'm really just guessing.

Best,
Ulrik

On Thu, 28 Jul 2016 at 12:36 <G.Maubach at weinwolf.de> wrote:

> Hi All,
>
> I need to spread a data.frame on 2 variables, e. g. "channel" and "unit".
>
> If I do it in two steps spreads keeps all cases that does not look like
> the one before although it contains the same values for a specific case.
>
> Here is what I have right now:
>
> -- cut --
>
> test1$dummy <- 1
> test2 <- spread(data = test1, key = 'channel', value = "dummy")
> test2
> cat("First spread is OK!")
>
> test2$dummy <- 1
> test3 <- spread(data = test2, key = 'unit', value = 'dummy')
>
> test1
> # test2
> test3
> warning(paste0("Second spread is not OK cause spread does not merge
> cases\n",
>                "with CustID 700 and 800 into one case,\n",
>                "cause they have values on different variables,\n",
>                "although the corresponding values of the cases with",
>                "custID 700 and 800 are missing."))
>
> cat("What I would like to have is:\n")
> target4 <- structure(list(custID = c(100, 200, 300, 500, 600, 700, 800,
> 900),
>   `10` = c(1, NA, NA, NA, NA, NA, NA, NA),
>   `20` = c(1, NA, NA, NA, NA, NA, NA, NA),
>   `30` = c(NA, NA, NA, NA, NA, NA, 1, 1),
>   `40` = c(NA, NA, NA, NA, 1, NA, 1, 1),
>   `50` = c(NA, NA, 1, NA, NA, NA, 1, 1),
>   `60` = c(NA, NA, NA, NA, NA, 1, NA, NA),
>   `70` = c(NA, NA, NA, NA, NA, 1, NA, NA),
>   `99` = c(NA, 1, NA, 1, NA, NA, NA, NA),
>   `1000` = c(1, NA, NA, NA, NA, NA, 1, 1),
>   `2000` = c(NA, NA, NA, NA, 1, 1, 1, NA),
>   `3000` = c(NA, NA, 1, NA, NA, 1, NA, NA),
>   `4000` = c(NA, NA, 1, NA, NA, NA, NA, NA),
>   `6000` = c(NA, NA, NA, NA, 1, NA, NA, NA),
>   `9999` = c(NA, 1, NA, 1, NA, NA, NA, NA)),
> .Names = c("custID",
>  "10",  "20",  "30",  "40",  "50",  "60",  "70",  "99",
>  "1000",  "2000",  "3000",  "4000",  "6000",  "9999"),
> row.names = c(NA, 8L), class = "data.frame")
>
> target4
>
> cat("What would be a proper way to create target4 from test1?")
>
> -- cut --
>
> What would be the proper way to create target4 from test1?
>
> Kind regards
>
> Georg
>
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