听写到列表/列表到听写

Posted 2021-02-25

Turning a dictionary into a list or an iterator is easy. To get a list of keys, you can just cast the dict into a list. It's cleaner, though to call .keys() on the dictionary to get a list of the keys, or .iterkeys() to get an iterator. Similarly, you can call .values() or .itervalues() to get a list or iterator of dictionary values. Remember though, that dicts are inherently unordered and so these values won't be in any meaningful order.

To preserve both keys and values, you can turn a dict into a list or iterator of 2-item tuples by using .items() or .iteritems(). This is something that you'll probably do a lot, and isn't very exciting:

# dicts to lists
 
dictionary = {'a': 1, 'b': 2, 'c': 3}
2dict_as_list = dictionary.items()
# dict_as_list now contains [('a', 1), ('b', 2), ('c', 3)]
 
 
# lists to dicts
 
dict_as_list = [['a', 1], ['b', 2], ['c', 3]]
dictionary = dict(dict_as_list)
# dictionary now contains {'a': 1, 'b': 2, 'c': 3}
 
# You can also combine this with the 'keyword arguments' method of creating a dict
 
dict_as_list = [['a', 1], ['b', 2], ['c', 3]]
dictionary = dict(dict_as_list, d=4, e=5)
# dictionary now contains {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}