List the periods available for a field — mds

Uses Solr facets to count, for each month, how many municipalities have a value for the field and how many of those values are non-zero.

Usage

mds_periods(field, localities = "BR", refresh = FALSE)

Arguments

field: A single field name (see mds_fields()).
localities: Localities to restrict the count to; same forms as in mds_data(). Default "BR".
refresh: Logical. Ignore the cached result and ask the API again? Default FALSE.

Value

A tibble with columns period ("YYYYMM"), n_localities and n_nonzero, ordered by period. The time of the request is kept in attr(x, "retrieved_at").

Details

The second count matters: the API returns 0 for months that have not been published yet (for instance, the BPC series carries zeros for every municipality up to the end of the current year). A month where n_nonzero is 0 for the whole selection is almost always unpublished, not a true zero. See mds_drop_unpublished().

Results are cached for the session. Large selections are counted in blocks of at most 200 municipality codes (the same split as mds_data()); the blocks do not overlap, so their counts are summed.

Examples

if (FALSE) { # interactive()
mds_periods("bpc_ben_i", localities = "PE")
}