hook_if: Supply an expression to identify which header groups are...
In ianmoran11/locatr: Easier Tidying of Data from Spreadsheets

This function is used with the .hook_if or .hook_if_rev arguments in the locate_groups function. This expression must evaluate to a single value for each header group. For example, see below that any(fmt_alignment_indent == 0) is used rather that fmt_alignment_indent == 0.

It passes an expression to dplyr::summarise that identifies which header groups are hooked

for example swiched from N to NNW. See the the locate_groups documentation for more information and an example.

1	hook_if(...)

...

expression applied to a identifies which header groups are hooked

## Not run: 


library(tidyverse)

# Read in tidyxl data frame
xl_df <-
  locatr_example("worked-examples.xlsx") %>%
  xlsx_cells_fmt(sheets = "pivot-hierarchy") %>%
  append_fmt(fmt_alignment_indent)

# Add location annotations
xl_df <-
  xl_df %>%
  locate_data(data_type == "numeric") %>%
  locate_groups(
    direction = "W",
    .groupings = groupings(fmt_alignment_indent),
    .hook_if = hook_if(any(fmt_alignment_indent == 0))
  ) %>%
  locate(direction = "N", name = student)

# Use `migrate` to reshape the data frame such that each data cells has its own row and each
 header variable has its own column.
xl_df %>% migrate()

## End(Not run)