Add weekdays to a neo4j time tree.

weekdays.r

library(RNeo4j)

graph = startGraph("http://localhost:7474/db/data/")

# Create time tree.
# Copied from http://www.markhneedham.com/blog/2014/04/19/neo4j-cypher-creating-a-time-tree-down-to-the-day/
timetree = "WITH range(2011, 2014) AS years, range(1,12) as months
            FOREACH(year IN years | 
              MERGE (y:Year {year: year})
              FOREACH(month IN months | 
                CREATE (m:Month {month: month})
                MERGE (y)-[:HAS_MONTH]->(m)
                FOREACH(day IN (CASE 
                                  WHEN month IN [1,3,5,7,8,10,12] THEN range(1,31) 
                                  WHEN month = 2 THEN 
                                    CASE
                                      WHEN year % 4 <> 0 THEN range(1,28)
                                      WHEN year % 100 <> 0 THEN range(1,29)
                                      WHEN year % 400 <> 0 THEN range(1,29)
                                      ELSE range(1,28)
                                    END
                                  ELSE range(1,30)
                                END) |      
                  CREATE (d:Day {day: day})
                  MERGE (m)-[:HAS_DAY]->(d))))"

cypher(graph, timetree)

# Generate dates from January 1st, 2011 to December 31st, 2014 by day.
dates = seq(from = as.Date("2011/1/1"), 
            to = as.Date("2014/12/31"), 
            by = "day")

# Extract day, month, year, and weekday from dates and store in data frame.
weekdays = data.frame(Day = format(dates, "%d"),
                      Month = format(dates, "%m"),
                      Year = format(dates, "%Y"),
                      Weekday = weekdays(dates))

# Write data frame to csv.
filepath = "C:/Users/Nicole/Desktop/weekdays.csv"
write.csv(weekdays, filepath, row.names = F)

# Use load csv to match the day and then add the weekday relationship.
load_csv = paste0("LOAD CSV WITH HEADERS FROM 'file:///", filepath, "' AS csv")

add_weekdays = paste(load_csv, 
                     "MATCH (d:Day {day:TOINT(csv.Day)})<-[:HAS_DAY]-(:Month {month:TOINT(csv.Month)})<-[:HAS_MONTH]-(:Year {year:TOINT(csv.Year)})
                      MERGE (w:Weekday {weekday:csv.Weekday})
                      CREATE (d)-[:ON_WEEKDAY]->(w)")

cypher(graph, add_weekdays)

# All days on a Wednesday in February of 2012. (2012 was a leap year)
cypher(graph, "MATCH (:Year {year:2012})-[:HAS_MONTH]->(:Month {month:2})-[:HAS_DAY]->(d:Day)-[:ON_WEEKDAY]->(:Weekday {weekday:'Wednesday'})
               RETURN d.day")

#   d.day
# 1     1
# 2     8
# 3    15
# 4    22
# 5    29