Defining a Dictionary
Dictionary is the Python term for an associative array. An array is, like a list, a series of values in two dimensions. An associative array gives one a way of accessing the values by a key, a term associated with the value instead of an item's index number.
Initializing a dictionary, one offsets the keys and values in curly braces. Each key-value pair is separated from the others by a comma. For each pair, the key and value are separated by a colon. The key of each member is offset in quotes. A sample dictionary is as follows:
my_dictionary = { "author" : "Andrew Melville",
"title" : "Moby Dick",
"year" : "1851",
"copies" : 5000000
}
Accessing a Dictionary
One accesses a dictionary member by its key:
>>> a = my_dictionary["author"]
>>> print a
Andrew Melville
To insert or modify a member, one simply assigns the value:
>>> my_dictionary["publisher"] = 'Harper and Brothers'
>>> my_dictionary["author"] = 'Herman Melville'
>>> print my_dictionary
{'publisher': 'Harper and Brothers', 'title': 'Moby Dick', 'year': '1851', 'copies': 5000000, 'author': 'Herman Melville'}