Pandas Vectorized Methods

>>> from pandas import Series, DataFrame
>>> d = {'one': Series([1,2,3], index=['a','b','c']),
... 'two': Series([1,2,3,4], index=['a','b','c','d'])}
>>> df = DataFrame(d)
>>> df
   one  two
a  1.0    1
b  2.0    2
c  3.0    3
d  NaN    4
>>> import numpy
>>> df.apply(numpy.mean)
one    2.0
two    2.5
dtype: float64
>>> df['one'].map(lambda x: x>= 1)
a     True
b     True
c     True
d    False
Name: one, dtype: bool
>>> df.applymap(lambda x: x>= 1)
     one   two
a   True  True
b   True  True
c   True  True
d  False  True
from pandas import DataFrame, Series
import numpy
def avg_bronze_medal_count():

    countries = ['Russian Fed.', 'Norway', 'Canada', 'United States',
                 'Netherlands', 'Germany', 'Switzerland', 'Belarus',
                 'Austria', 'France', 'Poland', 'China', 'Korea', 
                 'Sweden', 'Czech Republic', 'Slovenia', 'Japan',
                 'Finland', 'Great Britain', 'Ukraine', 'Slovakia',
                 'Italy', 'Latvia', 'Australia', 'Croatia', 'Kazakhstan']

    gold = [13, 11, 10, 9, 8, 8, 6, 5, 4, 4, 4, 3, 3, 2, 2, 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0]
    silver = [11, 5, 10, 7, 7, 6, 3, 0, 8, 4, 1, 4, 3, 7, 4, 2, 4, 3, 1, 0, 0, 2, 2, 2, 1, 0]
    bronze = [9, 10, 5, 12, 9, 5, 2, 1, 5, 7, 1, 2, 2, 6, 2, 4, 3, 1, 2, 1, 0, 6, 2, 1, 0, 1]
    
    olympic_medal_counts = {'country_name':Series(countries),
                            'gold': Series(gold),
                            'silver': Series(silver),
                            'bronze': Series(bronze)}
    olympic_medal_counts_df = DataFrame(olympic_medal_counts)
    bronze_at_least_one_gold = olympic_medal_counts_df['bronze'][olympic_medal_counts_df['gold'] >= 1]
    avg_bronze_at_least_one_gold = numpy.mean(bronze_at_least_one_gold)

    print(avg_bronze_at_least_one_gold)