Mutate between dates from external lookup table [duplicate]

Answer 1

You can use fuzzyjoin here :

fuzzyjoin::fuzzy_inner_join(df, date_lookup, 
           by = c('date' = 'start', 'date' = 'end'), match_fun = list(`>=`, `<=`))

# A tibble: 2 x 5
#  record date       start      end           id
#                   
#1 A      2020-02-15 2020-02-01 2020-02-28     2
#2 B      2020-01-03 2020-01-01 2020-01-31     1

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Using tidyverse functions :

tidyr::crossing(df, date_lookup) %>% dplyr::filter(date >= start, date <= end)