Tuple of string and list

Question

Lets say the days of the week are in a ordered list:

    days_week=['mon','tues','wed','thurs','fri','sat']

The function I'm making recieves a list of randomly occuring elements in days_week :

    random_list=['mon','mon','mon','wed','sat','fri','fri','wed']

And then it should output a tuple of the highest occuring day and a list of the occurences of each day in the the right order as in days_week eg all mon's first, then all tue's:

    output:('mon',[3,0,2,0,2,1])

My first thought was to build a dictionary of keys that are the names of the week, and values that are the occurences of those days:

    days_dictionary={}
    for i in random_list:
          if i in days_dictionary:
               days_dictionary[i]+=1
          else:
               days_dictionary[i]=1

and that's where I'm stuck because I'm not sure how I would use the dictionary to form the output above.

edit: i cant import anything other than math

Answer 1

you should be able to use these two expressions with your days_dictionary

>>> max(days_dictionary, key=days_dictionary.get)
'mon'
>>> [days_dictionary.get(k, 0) for k in days_week]
[3, 0, 2, 0, 2, 1]

Another way is to use a collections.Counter

>>> import random
>>> from collections import Counter
>>> days_week = ['mon', 'tues', 'wed', 'thurs', 'fri', 'sat']
>>> random_list = [random.choice(days_week) for x in range(10)]
>>> random_list
['wed', 'mon', 'mon', 'tues', 'tues', 'mon', 'wed', 'mon', 'wed', 'sat']
>>> c = Counter(random_list)
>>> c.most_common(1)[0][0]
'mon'
>>> [c.get(k, 0) for k in days_week]
[4, 2, 3, 0, 0, 1]
>>> c.most_common(1)[0][0], [c.get(k, 0) for k in days_week]
('mon', [4, 2, 3, 0, 0, 1])

Answer 2

I suggest having a look at itertools.groupby :

>>> days_week=['mon','tues','wed','thurs','fri','sat']
>>> import random
>>> random_list = [random.choice(days_week) for _ in range(10)]
>>> print random_list
['mon', 'fri', 'sat', 'wed', 'sat', 'thurs', 'wed', 'sat', 'tues', 'tues']
>>> import itertools
>>> g = itertools.groupby(sorted(enumerate(random_list), key=lambda x: x[1]), lambda x: x[1])
>>> for day, occur in g:
    print day, list(occur)


fri [(1, 'fri')]
mon [(0, 'mon')]
sat [(2, 'sat'), (4, 'sat'), (7, 'sat')]
thurs [(5, 'thurs')]
tues [(8, 'tues'), (9, 'tues')]
wed [(3, 'wed'), (6, 'wed')]

Answer 3

First: you can use collections.Counter to build your dictionary:

from collections import Counter
random_list = ['mon','mon','mon','wed','sat','fri','fri','wed']
counts = Counter(random_list)

Then you can build the frequency list like so:

days_week = ['mon','tues','wed','thurs','fri','sat']
freqs = [counts[d] for d in days_week if d in counts]

And for the final output:

output = counts.most_common(1)[0][0], freqs ## ('mon', [3, 2, 2, 1])

Answer 4

The first step is to get the most common day, like so:

import operator
most_common = max(days_dictionary.iteritems(), key=operator.itemgetter(1))[0]

then make the list of the rest of the occurrences

occur = [days_dictionary[day] for day in days_week]

then make the tuple

(most_common, occur)