1. basic
Dictionary is a special sequence.
b = {'name':'haha', 'age':12}
#in a dictionary, we have key and value.
#Key is immutable. Hence, key can be strings, numbers and tuples.
2. accessing values
b = {'name':'haha', 'age':12}
b['name'] # haha
3. update
b = {'name':'haha', 'age':12}
b['age'] = 8 #updating existing entry
b['Country'] = 'China' #add a new pair to the dictionary
4. delete
b = {'name':'haha', 'age':12}
del b['name'] #remove entry with key 'name'
b.clear() #remove all entries in b
del b #delete entire dictionary
5. properties
Duplicate key is not allowed.
#If we have duplicate key, the last wins.
b = {'name':'Ben', 'age':13, 'name':'Jack'}
b['name']#Jack
6. Built-in function
cmp(dict1, dict2) len(dict1) str(dict1) #Produces a printable string representation of a dictionary dict.clear() dict.copy() dict.fromkeys(str[, value]) #str is a sequence of new keys, If we have values, they will be the new value of the keys. Otherwise it will be none. dict.get(key, default=None) #For Key key, return value or default if key not in dictionary. dict.has_key(key) #return True, if dictionary has key dict.items() #Returns a list of dict's (key, value) tuple pairs dict.keys() #Returns list of dictionary dict's keys dict.setdefault(key, default=None) #Similar to get(), but will set dict[key]=default if key is not already in dict dict.update(dict2) #Adds dictionary dict2's key-values pairs to dict dict.values() #Returns list of dictionary dict's values