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Collapse Column(s)

collapse_col.Rd

Collapses values in the column(s) specified, concatenating unique values in those columns for each record (where a record is defined as a unique row including all columns NOT specified in .cols).

Usage

collapse_col(df, .cols, delim = "|", method = "unique", na.rm = FALSE)

Arguments

df

a data.frame

.cols

the name of the column in the data.frame to collapse

delim

A delimiter to place between vector elements (default: "|").

method

A string identifying a function to use; one of "unique", "first", or "last".

na.rm

A logical scalar indicating whether NA values should be removed (default: FALSE).

Value

A data.frame with the specified columns collapsed. Also NOTE the following:

  1. Collapsed columns will be converted to character.

  2. Rows will be reordered by the unique combination of columns not collapsed (due to dplyr::group_by() use).

See also

collapse_col_flex() for a more flexible approach and lengthen_col() for the pseudo-reverse operation that lengthens/expands one or more specified columns.

Examples

cc_df <- tibble::tibble(
     x = c(1, 2, 3, 3, 4, 4, 4),
     y = c("a", "a", "b", "b", "c", "c", "e"),
     z = c("Z", "Y", "X", "X", "W", "V", "U")
)
cc_df
#> # A tibble: 7 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     1 a     Z    
#> 2     2 a     Y    
#> 3     3 b     X    
#> 4     3 b     X    
#> 5     4 c     W    
#> 6     4 c     V    
#> 7     4 e     U    

# completely duplicated rows (3-4) are collapsed with any .cols specified
collapse_col(cc_df, y)
#> # A tibble: 6 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     1 a     Z    
#> 2     2 a     Y    
#> 3     3 b     X    
#> 4     4 e     U    
#> 5     4 c     V    
#> 6     4 c     W    

collapse_col(cc_df, x)
#> # A tibble: 6 × 3
#>   x     y     z    
#>   <chr> <chr> <chr>
#> 1 2     a     Y    
#> 2 1     a     Z    
#> 3 3     b     X    
#> 4 4     c     V    
#> 5 4     c     W    
#> 6 4     e     U    
collapse_col(cc_df, z)
#> # A tibble: 5 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     1 a     Z    
#> 2     2 a     Y    
#> 3     3 b     X    
#> 4     4 c     W|V  
#> 5     4 e     U    
collapse_col(cc_df, c(x, z))
#> # A tibble: 4 × 3
#>   x     y     z    
#>   <chr> <chr> <chr>
#> 1 1|2   a     Z|Y  
#> 2 3     b     X    
#> 3 4     c     W|V  
#> 4 4     e     U    

# negative & tidy selection works; all equivalent to collapse_col(cc_df, c(x, z))
collapse_col(cc_df, -y)
#> # A tibble: 4 × 3
#>   x     y     z    
#>   <chr> <chr> <chr>
#> 1 1|2   a     Z|Y  
#> 2 3     b     X    
#> 3 4     c     W|V  
#> 4 4     e     U    
collapse_col(cc_df, dplyr::matches("x|z"))
#> # A tibble: 4 × 3
#>   x     y     z    
#>   <chr> <chr> <chr>
#> 1 1|2   a     Z|Y  
#> 2 3     b     X    
#> 3 4     c     W|V  
#> 4 4     e     U    
collapse_col(cc_df, -dplyr::all_of("y"))
#> # A tibble: 4 × 3
#>   x     y     z    
#>   <chr> <chr> <chr>
#> 1 1|2   a     Z|Y  
#> 2 3     b     X    
#> 3 4     c     W|V  
#> 4 4     e     U