[R] Simple Stacking of Two Columns

[Marc Schwartz]

Hi,

You were on the right track using stack(), but you just pass the entire data frame as a single object, not the separate columns:

> stack(NamesWide)
  values   ind
1    Tom Name1
2   Dick Name1
3  Larry Name2
4  Curly Name2

Note that stack also returns the index (second column of 'ind' values), which tells you which column in the source data frame the stacked values originated from.

Thus, if you just want the actual data:

> stack(NamesWide)$values
[1] "Tom"   "Dick"  "Larry" "Curly"

returns a vector, or:

> stack(NamesWide)[, 1, drop = FALSE]
  values
1    Tom
2   Dick
3  Larry
4  Curly

which returns a data frame with a single column named 'values'.

Regards,

Marc Schwartz


On April 3, 2023 at 11:08:59 AM, Sparks, John (jspark4 using uic.edu (mailto:jspark4 using uic.edu)) wrote:

> Hi R-Helpers,
>
> Sorry to bother you, but I have a simple task that I can't figure out how to do.
>
> For example, I have some names in two columns
>
> NamesWide<-data.frame(Name1=c("Tom","Dick"),Name2=c("Larry","Curly"))
>
> and I simply want to get a single column
> NamesLong<-data.frame(Names=c("Tom","Dick","Larry","Curly"))
> > NamesLong
> Names
> 1 Tom
> 2 Dick
> 3 Larry
> 4 Curly
>
>
> Stack produces an error
> NamesLong<-stack(NamesWide$Name1,NamesWide$Names2)
> Error in if (drop) { : argument is of length zero
>
> So does bind_rows
> > NamesLong<-dplyr::bind_rows(NamesWide$Name1,NamesWide$Name2)
> Error in `dplyr::bind_rows()`:
> ! Argument 1 must be a data frame or a named atomic vector.
> Run `rlang::last_error()` to see where the error occurred.
>
> I tried making separate dataframes to get around the error in bind_rows but it puts the data in two different columns
> Name1<-data.frame(c("Tom","Dick"))
> Name2<-data.frame(c("Larry","Curly"))
> NamesLong<-dplyr::bind_rows(Name1,Name2)
> > NamesLong
> c..Tom....Dick.. c..Larry....Curly..
> 1 Tom  
> 2 Dick  
> 3 Larry
> 4 Curly
>
> gather makes no change to the data
> NamesLong<-gather(NamesWide,Name1,Name2)
> > NamesLong
> Name1 Name2
> 1 Tom Larry
> 2 Dick Curly
>
>
> Please help me solve what should be a very simple problem.
>
> Thanks,
> John Sparks
>
>
>
>
>
> [[alternative HTML version deleted]]
>
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