Step by Step solution about How to resolve the algorithm Day of the week step by step in the Julia programming language

This Julia code snippet generates a list of years between 2008 and 2121 (inclusive) in which Christmas (December 25th) falls on a Sunday. Here's a step-by-step explanation:

1. Importing the Dates Module:

   using Dates

   This line imports the Dates module, which provides functions for working with dates and times.

2. Defining the Year Range:

   lo, hi = 2008, 2121

   It defines the range of years to consider, from 2008 to 2121.

3. Generating the Christmas Dates:

   xmas = collect(Date(lo, 12, 25):Year(1):Date(hi, 12, 25))

   This line creates a list of Date objects representing Christmas (December 25th) for each year in the specified range. It uses the collect function to convert the generator expression Date(lo, 12, 25):Year(1):Date(hi, 12, 25) into a vector. The Year(1) part adds one year to the date in each iteration, effectively generating a sequence of Christmas dates from 2008 to 2121.

4. Filtering for Sundays:

   filter!(xmas) do dt
      dayofweek(dt) == Dates.Sunday
   end

   This part filters the xmas list to include only those dates that fall on a Sunday. It uses the filter! function, which modifies the original xmas list, removing any dates that don't meet the condition. The condition dayofweek(dt) == Dates.Sunday checks if the dt date falls on a Sunday, using the dayofweek function and comparing it to the Sunday value from the Dates module.

5. Printing the Results:

   println("Years from $lo to $hi having Christmas on Sunday: ")
   foreach(println, year.(xmas))

   Finally, it prints the years in which Christmas falls on a Sunday. It uses the println function to print the message, followed by a loop that prints each year using the year function on the filtered xmas list.

In summary, this code snippet generates a list of Christmas dates between 2008 and 2121 and filters it to include only those that fall on Sundays. It then prints the years in which Christmas falls on a Sunday.

using Dates

lo, hi = 2008, 2121
xmas = collect(Date(lo, 12, 25):Year(1):Date(hi, 12, 25))
filter!(xmas) do dt
    dayofweek(dt) == Dates.Sunday
end

println("Years from $lo to $hi having Christmas on Sunday: ")
foreach(println, year.(xmas))