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from __future__ import absolute_import, division, print_function


    

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# Create a [list] 
days = ['Monday', # multiple lines 
        'Tuesday', # acceptable 
        'Wednesday',
        'Thursday',
        'Friday',
        'Saturday',
        'Sunday', # trailing comma is fine!
       ]


    

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days


    

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# Simple for-loop
for day in days:
    print(day)


    

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# Double for-loop
for day in days:
    for letter in day:
        print(letter)


    

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print(days)


    

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print(*days)


    

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# Double for-loop
for day in days:
    for letter in day:
        print(letter)
    print()


    

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for day in days:
    for letter in day:
        print(letter.lower())


    

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length_of_days = [len(day) for day in days]
length_of_days


    

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letters = [letter for day in days
                    for letter in day]


    

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print(letters)


    

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letters = [letter for day in days for letter in day]
print(letters)


    

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[num for num in xrange(10) if num % 2]


    

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[num for num in xrange(10) if num % 2 else "doesn't work"]


    

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[num if num % 2 else "works" for num in xrange(10)]


    

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[num for num in xrange(10)]


    

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sorted_letters = sorted([x.lower() for x in letters])
print(sorted_letters)


    

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unique_sorted_letters = sorted(set(sorted_letters))


    

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print("There are", len(unique_sorted_letters), "unique letters in the days of the week.")
print("They are:", ''.join(unique_sorted_letters))


    

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print("They are:", '; '.join(unique_sorted_letters))


    

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def first_three(input_string):
    """Takes an input string and returns the first 3 characters."""
    return input_string[:3]


    

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import numpy as np


    

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# tab
np.linspace()


    

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[first_three(day) for day in days]


    

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def last_N(input_string, number=2):
    """Takes an input string and returns the last N characters."""
    return input_string[-number:]


    

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[last_N(day, 4) for day in days if len(day) > 6]


    

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from math import pi

print([str(round(pi, i)) for i in xrange(2, 9)])


    

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list_of_lists = [[i, round(pi, i)] for i in xrange(2, 9)]
print(list_of_lists)


    

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for sublist in list_of_lists:
    print(sublist)


    

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# Let this be a warning to you!

# If you see python code like the following in your work:

for x in range(len(list_of_lists)):
    print("Decimals:", list_of_lists[x][0], "expression:", list_of_lists[x][1])


    

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print(list_of_lists)

# Change it to look more like this: 

for decimal, rounded_pi in list_of_lists:
    print("Decimals:", decimal, "expression:", rounded_pi)


    

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# enumerate if you really need the index

for index, day in enumerate(days):
    print(index, day)


    

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from IPython.display import IFrame, HTML
HTML('<iframe src=https://en.wikipedia.org/wiki/Hash_table width=100% height=550></iframe>')


    

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fellows = ["Jonathan", "Alice", "Bob"]
universities = ["UCSD", "UCSD", "Vanderbilt"]


    

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for x, y in zip(fellows, universities):
    print(x, y)


    

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# Don't do this
{x: y for x, y in zip(fellows, universities)}


    

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# Doesn't work like you might expect
{zip(fellows, universities)}


    

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dict(zip(fellows, universities))


    

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fellows


    

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fellow_dict = {fellow.lower(): university 
                   for fellow, university in zip(fellows, universities)}


    

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fellow_dict


    

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fellow_dict['bob']


    

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rounded_pi = {i:round(pi, i) for i in xrange(2, 9)}


    

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rounded_pi[5]


    

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sum([i ** 2 for i in range(10)])


    

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sum(i ** 2 for i in range(10))


    

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huh = (i ** 2 for i in range(10))


    

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huh.next()