Learning Ruby

Write a series of scripts that do the following and save each one:

• Script 1: read a list of arguments from the command prompt and print them out

• Script 2: print the arguments as a comma-separated list (Array#join)

  • FIX: The output of script2.rb a b c d should be a, b, c, d

• Script 3: Take JSON file path from the command line and verify the file exists, print a message to the screen saying so; add a message to print when the file does not.

  • FIX: Script 3 should take an argument script3.rb data/manifest.json; the script now hard codes the path and the file exists tests will always evaluate to true; when the file does not exist the script should print a different message:

$ ruby script3.rb data/manifest.xyz # => "File does not exist: data/manifest.xyz

• Script 4: Open one JSON file and print each line to the screen, using

File.open do |f|
end

• CHANGE: If time permits, change this script to accept an argument so it will work with any text file.

Do you get a blank line between each printed line? If so, why? How do you fix it without using a regular expression?

• Script 5: Open one JSON file and load it using the JSON library and print the top level keys

• Script 6: Open one JSON file and print each image @id, getting each ID using Hash bracket [] notation

• Script 7: Open one JSON file and print each image @id using, getting each @id using Hash#dig

  • OOPS: My bad, the manifest was a bad choice here. It doesn't really exercise the Hash#dig method. So, do this, open and load data/dir2/ds-catalog-dump-20230328.json and use Hash#dig to get the value for each top-level hash in the list (thing['labels']['en']['value']). Note that they all have labels.

• Script 7b: Following the OOPS above, load the same file, data/dir2/ds-catalog-dump-20230328.json, then

  • Find each item (thing['type'] == 'item')
  • Find get all the claims hashes (e.g., thing['claims']['P16'].each { |claim| .. })
  • For each one of these claims print the id using bracket notation (i.e., claim['mainsnak'][...])
  • The above should break; why?
  • Now do the same using Hash#dig; this shouldn't break

The next scripts don’t deal with JSON; so, you’re starting over

• Script 8: Open your ARK list and print each line to the screen, using the File.open() do |f| ... end block.

  • OOPS, again: There's only one ARK here. Do you have a file with more ARK IDs you could use here?

• Script 9: Re-implement your normalize_string method, open your ARK list, and print each normalized string to the screen; use the do ... end block; try the /.../ and %r(...) notations.

• Script 10: Open the ark list and print each IIIF manifest URL to the screen using string interpolation.

Working with directories

• Script 11: Accept a directory as an argument; read each file name and print to the screen prefix --- File: before each file name; run this on data/dir1 and data/dir2

• Script 12: Same as script 11 for data/dir2 and data/dir3, but also print the prefix with the file extension:

-- File, txt: some_file.txt
-- File, csv: some_other_file.csv
etc.

• Script 13: Accept a directory as an argument; select the CSV files; use Dir[] with globbing; print each file name to the screen prefixing each with ---

• Script 14a: Same as script 13, but read all the files from the directory and use Enumerable#select with a block to select the CSV files.

• Script 14b: Same as script 14a, except use Enumerable#reject to select the CSV files.

Working with images

Prep

Install ImageMagick: brew install ImageMagick Install the Rmagick gem: gem install rmagick

• Script 15: Download web JPEGs for LJS 108 into a new folder.

• Script 16: Combine the JPEGs for LJS 108 as a single PDF; output the PDF to a separate folder.

• Script 17: Download web JPEGs for LJS 108 into a new folder; combine them as a single PDF; output the PDF to a separate folder; delete the JPEGs after.

Useful pages

These pages from https://ruby-doc.org will be helpful:

Array https://ruby-doc.org/3.2.2/Array.html

Array mixes in all these methods: https://ruby-doc.org/3.2.2/Enumerable.html

Dir: directory operations https://ruby-doc.org/3.2.2/Dir.html

Dir[] and Dir.glob https://ruby-doc.org/3.2.2/Dir.html#method-c-glob

Enumerable#select https://ruby-doc.org/3.2.2/Enumerable.html#method-i-select

Enumerable#reject https://ruby-doc.org/3.2.2/Enumerable.html#method-i-reject

File https://ruby-doc.org/3.2.2/File.html

FileUtils https://ruby-doc.org/3.2.2/stdlibs/fileutils/FileUtils.html

For equivalents to rm, cp, mv, etc.

Hash https://ruby-doc.org/3.2.2/Hash.html

JSON https://ruby-doc.org/3.2.2/exts/json/JSON.html

open-uri https://ruby-doc.org/3.2.2/stdlibs/open-uri/OpenURI.html

Downloading files with OpenURI https://www.twilio.com/blog/download-image-files-ruby

Regular expressions https://ruby-doc.org/3.2.2/Regexp.html

RMagick https://rmagick.github.io | https://github.com/rmagick/rmagick

Using Rmagick to combine images in one PDF https://stackoverflow.com/a/20638567

String https://ruby-doc.org/3.2.2/String.html

Note especially: String#sub, String#gsub, String.chomp, String.strip