lesson3.py

# Data Structures
# 1. Lists
# 1.1 List indexing

month = 8
days_in_month = [31,28,31,30,31,30,31,31,30,31,30,31]

# use list indexing to determine the number of days in month

num_days=days_in_month[month + 1]
print(num_days)

# Slicing lists

eclipse_dates = ['June 21, 2001', 'December 4, 2002', 'November 23, 2003',
                 'March 29, 2006', 'August 1, 2008', 'July 22, 2009',
                 'July 11, 2010', 'November 13, 2012', 'March 20, 2015',
                 'March 9, 2016']
                 
                 
# TODO: Modify this line so it prints the last three elements of the list
print(eclipse_dates[-3:])

# Functions for lists
# len, max, min and Lists

a = [1, 5, 8]
b = [2, 6, 9, 10]
c = [100, 200]

print(max([len(a), len(b), len(c)]))
print(min([len(a), len(b), len(c)]))

# sorted, join and Lists

names = ["Carol", "Albert", "Ben", "Donna"]
print(" & ".join(sorted(names)))

# append and Lists

names = ["Carol", "Albert", "Ben", "Donna"]
names.append("Eugenia")
print(sorted(names))

print(" & ".join(sorted(names)))

# Quiz

arr = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
print(arr[0])

# Print ['c', 'd', 'e', 'f']

print(arr[2:6])

# Print ['a', 'b', 'c']

print(arr[:3])

# Print ['e', 'f', 'g']

print(arr[4:])

# Dictionaries 

# Define a Dictionary, population,
# that provides information
# on the world's largest cities.
# The key is the name of a city
# (a string), and the associated
# value is its population in
# millions of people.

#   Key     |   Value
# Shanghai  |   17.8
# Istanbul  |   13.3
# Karachi   |   13.0
# Mumbai    |   12.5


population={'Shanghai':17.8, 
			'Istanbul':13.3, 
			'Karachi':13.0, 
			'Mumbai':12.5}

# Compound data structures

elements = {'hydrogen': 
				{'number': 1, 'weight': 1.00794, 'symbol': 'H', 'is_noble_gas': False},
            'helium': 
            	{'number': 2, 'weight': 4.002602, 'symbol': 'He', 'is_noble_gas': True}}

# todo: Add an 'is_noble_gas' entry to the hydrogen and helium dictionaries
# hint: helium is a noble gas, hydrogen isn't

print(elements['hydrogen']['is_noble_gas'])
print(elements['helium']['is_noble_gas'])

# Practice questions


verse = "if you can keep your head when all about you are losing theirs and blaming it on you   if you can trust yourself when all men doubt you     but make allowance for their doubting too   if you can wait and not be tired by waiting      or being lied about  don't deal in lies   or being hated  don't give way to hating      and yet don't look too good  nor talk too wise"
print(verse, '\n')

# split verse into list of words
verse_list = verse.split()
print(verse_list, '\n')

# convert list to a data structure that stores unique elements
verse_set = set(verse_list)
print(verse_set, '\n')

# print the number of unique words
num_unique = len(verse_set)
print(num_unique, '\n')

verse_dict =  {'if': 3, 'you': 6, 'can': 3, 'keep': 1, 'your': 1, 'head': 1, 'when': 2, 'all': 2, 'about': 2, 'are': 1, 'losing': 1, 'theirs': 1, 'and': 3, 'blaming': 1, 'it': 1, 'on': 1, 'trust': 1, 'yourself': 1, 'men': 1, 'doubt': 1, 'but': 1, 'make': 1, 'allowance': 1, 'for': 1, 'their': 1, 'doubting': 1, 'too': 3, 'wait': 1, 'not': 1, 'be': 1, 'tired': 1, 'by': 1, 'waiting': 1, 'or': 2, 'being': 2, 'lied': 1, 'don\'t': 3, 'deal': 1, 'in': 1, 'lies': 1, 'hated': 1, 'give': 1, 'way': 1, 'to': 1, 'hating': 1, 'yet': 1, 'look': 1, 'good': 1, 'nor': 1, 'talk': 1, 'wise': 1}
print(verse_dict, '\n')

# find number of unique keys in the dictionary
num_keys = len(verse_dict)
print(num_keys)

# find whether 'breathe' is a key in the dictionary
contains_breathe = 'breathe' in verse_dict
print(contains_breathe)

# create and sort a list of the dictionary's keys
sorted_keys = sorted(verse_dict.keys())
print(sorted_keys)

# get the first element in the sorted list of keys
print(sorted_keys[0])

# find the element with the highest value in the list of keys
print(sorted_keys[-1])