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Collapse Column(s) Flexibly

collapse_col_flex.Rd

Collapses values in the column(s) specified using a defined method for each record, where a record is defined as a unique observation comprised of all columns NOT specified in collapse).

Usage

collapse_col_flex(df, ..., method = "unique", delim = "|")

Arguments

df

A data.frame

...

Column-method pairs specifying the method to use for each column to be collapsed; column names can be bare variables or strings, methods must be strings, e.g. column_name = method.

method

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

delim

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

Value

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

  1. For all methods, rows will be reordered by the unique combination of columns not collapsed (due to dplyr::group_by() use).

  2. _For "unique" method, collapsed columns will be converted to character.

See also

collapse_col() for a simpler 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 column(s) specified
collapse_col_flex(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    

# individual columns
collapse_col_flex(cc_df, z, method = "unique")
#> # 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_flex(cc_df, z, method = "first")
#> # 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    
#> 5     4 e     U    
collapse_col_flex(cc_df, z, method = "last")
#> # 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     V    
#> 5     4 e     U    

# multiple columns can be collapsed using the same method
collapse_col_flex(cc_df, x, z, method = "unique")
#> # 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_flex(cc_df, x, z, method = "first")
#> # A tibble: 4 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     1 a     Z    
#> 2     3 b     X    
#> 3     4 c     W    
#> 4     4 e     U    
collapse_col_flex(cc_df, x, z, method = "last")
#> # A tibble: 4 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     2 a     Y    
#> 2     3 b     X    
#> 3     4 c     V    
#> 4     4 e     U    

# ...or using different methods
collapse_col_flex(cc_df, x = "unique", z = "unique")
#> # 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_flex(cc_df, x = "first", z = "unique")
#> # A tibble: 4 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     1 a     Z|Y  
#> 2     3 b     X    
#> 3     4 c     W|V  
#> 4     4 e     U    
collapse_col_flex(cc_df, x = "first", z = "last")
#> # A tibble: 4 × 3
#>       x y     z    
#>   <dbl> <chr> <chr>
#> 1     1 a     Y    
#> 2     3 b     X    
#> 3     4 c     V    
#> 4     4 e     U