In [2]:

    

x = [1, 2, 3]
y = [4, 5, 6]
z = [10, 12, 15, 17]

zip(x, y, z)


    

    
Out[2]:





[(1, 4, 10), (2, 5, 12), (3, 6, 15)]

In [3]:

    

a = [1, 2, 3, 4, 5]
b = [2, 2, 10, 1, 1]

for pair in zip(a,b):
    print max(pair)


    

    




2
2
10
4
5

In [4]:

    

# each iteration of a element here, which would be a tuple generated by
# zip(), gets evaluated with max() in order to return a single, large value. 
map(lambda pair: max(pair), zip(a,b))


    

    
Out[4]:





[2, 2, 10, 4, 5]

In [18]:

    

def switcharoo(d1, d2):
    dout = {}
    for k1, v2 in zip(d1, d2.itervalues()): #this zip creates the list of tuple ahead of time, and then iterates over it
        dout[k1] = v2
    return dout


    

In [19]:

    

dic1 = {'a':10, 'b':20}
dic2 = {'c':-20, 'd':-10}

switcharoo(dic1, dic2)


    

    
Out[19]:





{'a': -20, 'b': -10}

In [32]:

    

'''
todos:
1. wtf is sentinel = object() for? is it a common code design pattern 
2. why the * usage in parameter? is there reference/value aka, pointer, passing in python?
3. wtf is the yield reserved word do
'''
def zip(*iterables):
    # zip('ABCD', 'xy') --> Ax By
    sentinel = object()
    iterators = [iter(it) for it in iterables]
    while iterators:
        result = []
        for it in iterators:
            elem = next(it, sentinel)
            if elem is sentinel:
                return
            result.append(elem)
        yield tuple(result)


    

In [21]:

    

l = ['a', 'b', 'c']
count = 0
for item in l:
    print count
    print item
    count += 1


    

    




0
a
1
b
2
c

In [22]:

    

for count,item in enumerate(l):
    print count, item


    

    




0 a
1 b
2 c

In [33]:

    

'''
Functionally equivalent def for enumerate built-in
'''
def enumerate(sequence, start=0):
    n = start
    for elem in sequence:
        yield n, elem
        n += 1


    

In [23]:

    

'''
Very simply: all() checks that all members of a list evalue to True whereas
any() check that at least 1 evaluates to true
'''

l_bool = [True, False, True, True]
any(l_bool)


    

    
Out[23]:





True

In [24]:

    

all(l_bool)


    

    
Out[24]:





False

In [30]:

    

is_weekend = True
is_vacation = False
is_before_noon = True
snooze_alarm_requirements = [is_weekend, is_vacation, is_before_noon]

if any(snooze_alarm_requirements):
    print("Snooze the alarm, it's too early")

if all(snooze_alarm_requirements):
    print("Come back later, ain't no body got time for this")
else:
    print("Really wished is was before noon, on a saturday on my vacation")


    

    




Snooze the alarm, it's too early
Really wished is was before noon, on a saturday on my vacation

In [34]:

    

def all(iterable):
    for element in iterable:
        if not element:
            return False
    return True

def any(iterable):
    for element in iterable:
        if element:
            return True
    return False


    

In [ ]: