Christian Weber, Senior Solutions Engineer github.com/webdog [email protected] @classicwebdog Engineering Pop Songs with Python 

whoami @classicwebdog • Python is the best 

whoami @classicwebdog • I play some instruments 

whoami @classicwebdog • This was hard! 

whoami @classicwebdog • If you don’t know python/music, you’ll learn something new • If you know python/music, consider this a refresher • I’ll learn something from you 

Key takeaways for today @classicwebdog • The art of the possible • Learn stuff about python • Learn some music theory! 

Music @classicwebdog 

Notes - The Chromatic Scale @classicwebdog 

How it looks on a piano @classicwebdog 

Sheet Music - The Structure of Music @classicwebdog 

Understanding the staff @classicwebdog 

Let’s see that sheet music again @classicwebdog 

Major Scale - The equation 1/2 T 1/2 T S 1/2 T 1/2 T 1/2 T S I/Root 2 3 4 5 6 7 Octave C C# D D# E F F# G G# A A# B C G G# A A# B C C# D D# E F F# G R, T, T, S, T, T, T, S @classicwebdog 

Chords in the major scale 1 2 3 4 5 6 7 Chord C D E F G A B CMaj D E F G A B C Dmin E F G A B C D Emin F G A B C D E FMaj G A B C D E F GMaj A B C D E F G Amin B C D E F G A Bdim @classicwebdog 

Python @classicwebdog 

Express Yourself print("I really love The Beatles" >>> “I really love The Beatles” def fav_band(band): return f'My favorite band is {band}' fav_band("The Beatles”) >>>My favorite band is The Beatles @classicwebdog 

• Integers • Floats Express Yourself • Booleans • Strings @classicwebdog 

Representing and Structuring Data strings = "Hey ho let's go" strings.split(" ") # ["Hey", "Ho", "let's", "go"] beatles_songs = ["Let it Be", "Yesterday", "I wanna hold your hand"] song = lists[0] # "Let it Be” song = lists[-1] # “I wanna hold your hand” michael_jackson = ("Thriller", "Beat It", "You are not alone") mj_songs = michael_jackson[-1] # Nope! Doesn’t work! Why? best_punk_bands_by_year = { 1993: "Green Day", 1994: "Rancid", 1995: "Blink 182", 1996: "Mighty Mighty Bosstones" } best_punk_bands_by_year[1993] # Green Day best_punk_bands_by_year.keys() # dict_keys([1993, 1994, 1995, 1996]) @classicwebdog 

How can we execute certain code? def time_signature(time_sig): if time_sig == 4: print("We're going to play in 4/4 time") return True elif time_sig == 3: print("We're going to play in 3/4 time") return True else: print("Unsupported time signature!") return False @classicwebdog 

How can we represent `things`? • First we had data types • Then we talked about conditionals • Moving on to functions • Can we go higher? Yes! @classicwebdog 

A single Class class Notes(object): notes = ["C","C#/Db","D","D#/Eb","E","F","F#/Gb","G","G#/Ab","A","A#/Bb","B"] def calculate_total_notes(self): return len(self.notes) @classicwebdog 

Inheritance @classicwebdog 

Class with Inheritance class Notes(object): notes = ["C","C#/Db","D","D#/Eb","E","F","F#/Gb","G","G#/Ab","A","A#/Bb","B"] def calculate_total_notes(self): return len(self.notes) class Music(Notes): def __init__(self, scale): self.scale = scale def major(self): if self.scale == "major": scale_list = [] for note in self.notes: if "/" in note: pass else: scale_list.append(note) return scale_list else: return None @classicwebdog 

metaclasses and dunder methods @classicwebdog class Notes(object): notes = ["C","C#/Db","D","D#/Eb","E","F","F#/Gb","G","G#/Ab","A","A#/Bb","B"] def calculate_total_notes(self): return len(self.notes) class Music(Notes): def __init__(self, scale): self.scale = scale def __str__(self): return f'Class for the {self.scale} scale. Also has these notes from the chromatic scale: {self.notes}' def __repr__(self): return f'' def major(self): if self.scale == "major": scale_list = [] for note in self.notes: if "/" in note: pass else: scale_list.append(note) return scale_list else: return None 

Python + Music @classicwebdog 

Joining forces @classicwebdog 

Chord Progressions = More structure @classicwebdog 1 2 3 4 5 6 7 Chord C D E F G A B CMaj D E F G A B C Dmin E F G A B C D Emin F G A B C D E FMaj G A B C D E F GMaj A B C D E F G Amin B C D E F G A Bdim 

Chord Progressions = More structure @classicwebdog 1 2 3 4 5 6 7 Chord C D E F G A B CMaj I D E F G A B C Dmin ii E F G A B C D Emin iii F G A B C D E FMaj IV G A B C D E F GMaj V A B C D E F G Amin vi B C D E F G A Bdim vii 

The most common chord progression of them all @classicwebdog I - V-vi -IV or… C - G - Am - F 

How are songs typically structured? @classicwebdog • Verse (8 bars) • Chorus (4 bars) • Verse (8 bars) • Chorus (4 bars) 

Generating “random” lyrics @classicwebdog import random class Lyrics(object): adjective = ["everyday", "sometimes", "occasionally", "significantly", "excited"] verbs = ["excuse", "absorb", "kiss", "drop", "isolate", "fling"] nouns = ["head", "heart", "skin", "air", "chair", "carpet"] adverbs = ["dutifully", "crazily", "realistically", "heartfully", "foolishly"] contractions = ["don't", "can't", "won't", "hasn't", "must've"] identifier = ["I", "She", "He", "They", "We"] def random_verse(self, bars=8): verses = [] for i in range(bars): random_num = random.randrange(0, len(self.adjective)) rand_verse = self.identifier[random_num] + ' ' + self.contractions[random_num] + ' ' + self.adverbs[random_num] +' ' + self.nouns[random_num] + ' ' + self.verbs[random_num] + ' ' + self.adjective[random_num] verses.append(rand_verse) return verses 

Generating the progression @classicwebdog import random class Song(Music): def __init__(self, progression): self.progression = progression def is_pop(self): if self.progression == "pop": notes = self.major() prog_dict = {} for note in notes: if note == "C": prog_dict["CMaj"] = 1 elif note == "F": prog_dict["FMaj"] = 4 elif note == "G": prog_dict["GMaj"] == 5 elif note == "A": prog_dict["Amin"] == 6 else: pass return prog_dict else: return None 

Represented as code @classicwebdog c = l.random_chorus() chords = [keys for keys in s.is_pop()] for i in l.random_verse(): r = random.randrange(0, len(chords)) print(chords[r]) print(i) print("\n") for i in c: print(chords[0], chords[1], chords[2], chords[3]) print(i) print("\n") for i in l.random_verse(): r = random.randrange(0, len(chords)) print(chords[r]) print(i) print("\n") for i in c: print(i) 

Outputs some…interesting results @classicwebdog FMaj They hasn't heartfully air drop significantly GMaj They hasn't heartfully air drop significantly CMaj She can't crazily heart absorb sometimes FMaj They hasn't heartfully air drop significantly CMaj She can't crazily heart absorb sometimes Amin They hasn't heartfully air drop significantly GMaj He won't realistically skin kiss occasionally GMaj She can't crazily heart absorb sometimes CMaj FMaj GMaj Amin We must've foolishly chair isolate excited CMaj FMaj GMaj Amin We must've foolishly chair isolate excited CMaj FMaj GMaj Amin We must've foolishly chair isolate excited CMaj FMaj GMaj Amin We must've foolishly chair isolate excited GMaj I don't dutifully head excuse everyday Amin I don't dutifully head excuse everyday FMaj We must've foolishly chair isolate excited GMaj He won't realistically skin kiss occasionally Amin I don't dutifully head excuse everyday GMaj I don't dutifully head excuse everyday GMaj She can't crazily heart absorb sometimes GMaj They hasn't heartfully air drop significantly We must've foolishly chair isolate excited We must've foolishly chair isolate excited We must've foolishly chair isolate excited We must've foolishly chair isolate excited 

Next time… @classicwebdog • How could we get this into a testable format? • Could we dynamically re-engineer a MIDI like this? • Who is going to sing the crazy lyrics? 

Thanks! @classicwebdog