Identify these famous people by their initials (based on their full names), and explain the outlandish arithmetic used here. Whose initials should come at the question mark?

Assignment

We work with text files containing information about asteroids named after famous people. Each line of such a file describes one asteroid by four semicolons-separated (;) information fields: i) the unique number of the asteroid according to the International Astronomical Union’s Minor Planet Center³, ii) the unique name of the asteroid, iii) the full name of the person the asteroid was named after and iv) a short description of that person. For example, these are some lines from such a file (asteroids.txt⁴):

...
316020;Linshuhow;Jeremy Shu-How Lin;basketball player
316201;Malala;Malala Yousafzai;a Pakistani activist for female education
326290;Akhenaten;Akhenaten;a pharaoh of the 18th Dynasty of Egypt
327695;Yokoono;Yoko Ono;musician
337044;Bobdylan;Robert Allen Zimmerman;musician
342843;Davidbowie;David Robert Jones;musician
347940;Jorgezuluaga;Jorge I. Zuluaga Callejas;Colombian astronomer
365443;Holiday;Billie Holiday;jazz musician
374354;Pesquet;Thomas Gautier Pesquet;French astronaut
495181;Rogerwaters;George Roger Waters;musician, one of Pink Floyd founders
495253;Hanszimmer;Hans Florian Zimmer;a German composer
560354;Chrisnolan;Christopher Edward Nolan;film director

Your task:

• Write a function initials that takes the full name (str) of a person. The function must return the initials (str) of that person, consisting of all letters in the person's full name that are not directly preceded by a letter.

• Write a function read_asteroids that takes the location (str) of a text file containing information about asteroids named after famous people. The function must return a dictionary (dict) that maps the numbers (int) of all asteroids in the file onto a tuple (tuple) with two strings (str): i) the unique name of the asteroid and ii) the full name of the person the asteroid was named after. We call this the dictionary representation of the asteroids from the file.

• Write a function group that takes the dictionary representation $$\mathcal{A}$$ of the asteroids from a file. The function must return a new dictionary (dict) that maps the initials (str) of each person in $$\mathcal{A}$$ onto a set (set) containing the numbers (int) of all asteroids in $$\mathcal{A}$$ that are named after persons with those initials. Use full names of persons to determine their initials.

• Write a function rock_legends that takes three arguments: the initials $$i_1$$ and $$i_2$$ (str) of two persons, and the dictionary representation $$\mathcal{A}$$ of the asteroids from a file. The function must return a set (set) containing all asteroids in $$\mathcal{A}$$ whose number can be written as the sum of an asteroid in $$\mathcal{A}$$ that was named after a person with initials $$i_1$$ and the number of an asteroid in $$\mathcal{A}$$ that was named after a person with initials $$i_2$$. The function also has an optional parameter persons, taking a Boolean value (bool) that determines whether the asteroids in the set are represented by their name (False; default value) or by the full name of the person they are named after (True).

Example

In the following interactive session we assume the text file asteroids.txt⁵ to be located in the current directory .

>>> initials('William Shakespeare')
'WS'
>>> initials('Johann Wolfgang von Goethe')
'JWvG'
>>> initials('Muḥammad ibn Mūsā al-Khwārizmī')
'MiMaK'

>>> asteroids = read_asteroids('asteroids.txt6')
>>> asteroids[2985]
('Shakespeare', 'William Shakespeare')
>>> asteroids[3047]
('Goethe', 'Johann Wolfgang von Goethe')
>>> asteroids[11156]
('Al-Khwarismi', 'Muḥammad ibn Mūsā al-Khwārizmī')

>>> init2aster = group(asteroids)
>>> init2aster['WS']
{2985, 31556}
>>> init2aster['JWvG']
{3047}
>>> init2aster['MiMaK']
{11156, 13498}

>>> rock_legends('WS', 'JWvG', asteroids)
{'Nobel'}
>>> rock_legends('DFJA', 'JS', asteroids, True)
{'Charles IV', 'David Morrison', 'Gregor Johann Mendel'}
>>> rock_legends('JP', 'JS', asteroids, persons=True)
{'Andrew Ferrari', 'Grace Patricia Kelly', 'James Francis Cagney Jr.', 'Lynn Rene Anderson'}

Epilogue

Strangely, asteroid 2309 Mr. Spock caused an uproar when its discoverer — James Gibson — revealed that he had actually named it after his cat (he called the cat Spock because it was "imperturbable, logical, intelligent, and had pointed ears"). The International Astronomical Union⁷ officially discouraged any more pet names, but people are still fine — asteroids have been named after Carlos Santana, James Bond, all four Beatles and all six members of Monty Python.

By the way, did you know that Brian Harold May⁸ — lead guitarist of the rock band Queen⁹ — earned a PhD degree in astrophysics from Imperial College London¹⁰ in 2007. From 2008–2013 he was Chancellor of Liverpool John Moores University¹¹ and he was a "science team collaborator" with NASA's New Horizons¹² Pluto mission. He is also a co-founder of the awareness campaign Asteroid Day¹³ and asteroid 52665 Brianmay¹⁴ was named after him.