Python Data Structures and Algorithms

Dictionaries

Dictionaries are arbitrary collections of objects indexed by numbers, strings, or other immutable objects. Dictionaries themselves are mutable; however, their index keys must be immutable. The following table contains all the dictionary methods and their descriptions:

Method	Description
len(d)	Number of items in d.
d.clear()	Removes all items from d.
d.copy()	Makes a shallow copy of d.
d.fromkeys(s [,value])	Returns a new dictionary with keys from sequence s and values set to value.
d.get(k [,v])	Returns d[k] if found, or else returns v, or None if v is not given.
d.items()	Returns a sequence of key:value pairs in d.
d.keys()	Returns a sequence of keys in d.
d.pop(k [,default]) ...