Promote a mis-placed header row and drop leading metadata rows

When a banner / blank / units / repeated-label row sits ABOVE the real header, the reader takes that top row as the header (inventing ...N names, or spreading one label – CDA merged across 110 columns – into CDA...1 ... CDA...110). This finds the true header among the first few rows via .detect_header_row(), promotes it to the column names, drops it and everything above, and re-types the freed columns. It is the inverse of data_strip_qualtrics_header() (which strips junk rows BELOW a correct header).

Usage

data_promote_header_row(df, raw_rows = NULL, max_scan = 4L)

Arguments

df

the data.frame as normally read (reader-assigned names)

raw_rows

optional list of character vectors: the first rows of the file read WITHOUT a header, so the reader-swallowed header row is visible. When supplied it is the authoritative scan window.

max_scan

how many leading rows to consider as metadata above the header

Value

a list with df (possibly re-headed), promoted (1-based count of metadata rows removed above the header, 0 = unchanged), and stripped (character vectors of those removed rows, for reporting).

Details

The input must be read so that the real header is still a DATA row (i.e. read headerless, or with the reader's own header as row-0 metadata). Pass the rows via raw_rows (the file re-read headerless as character) so the detector can see the row the reader swallowed as the header; without it the function falls back to treating df's own first rows as the scan window.

Examples

# a title row above the real header, read as the header
df <- data.frame(`Stroop study export` = c("id", "1", "2", "3"),
                 X = c("rt", "512", "640", "498"), check.names = FALSE)
res <- data_promote_header_row(df)
res$promoted
#> [1] 1
res$df
#>   id  rt
#> 1  1 512
#> 2  2 640
#> 3  3 498