color_count.py

colors_list = ['blue', 'blue', 'green', 'yellow',
    'blue', 'green', 'red']


sample_dict = {
    'a': 1,
    'b': 'hello',
    'c': [1, 2, 3]
}

sample_dict['c']

# value
sample_dict['a']

# not existing -> KeyError

# or with .get(): no KeyError, None
sample_dict.get('a')
sample_dict.get('a', 'hello')

# left side: .keys()

# py2
sample_dict.keys()

# py3
list(sample_dict.keys())

# right side: .values()
# (key, value): .items()
# 1. keys are unique
# 2. keys are not ordered
# test if key exists in dict: 'key' in mydict


# if key in dict
def count_colors_if(colors_list):
    counts = dict()
    for color in colors_list:
        if color in counts:
            counts[color] += 1
            # counts[color] = counts[color] + 1
        else:
            counts[color] = 1

        print counts
    return counts


# dict.get()
def count_colors_get(colors_list):
    counts = dict()
    for color in colors_list:
        counts[color] = counts.get(color, 0) + 1
        print counts
    return counts


# dict.setdefault()
def count_colors_setdefault(colors_list):
    counts = dict()
    for color in colors_list:
        counts.setdefault(color, 0)
        counts[color] += 1
        print counts
    return counts


# dict.fromkeys()
def count_colors_fromkeys(colors_list):
    counts = dict.fromkeys(colors_list, 0)
    for color in colors_list:
        counts[color] += 1
    return counts


# list.count() + set()
def count_colors_count_set(colors_list):
    counts = dict()
    for color in set(colors_list):
        counts[color] = colors_list.count(color)
    return counts