Summary of Python dictionary operations

1.dict() create the dictionary

>>> fdict = dict((['x', 1], ['y', 2]))

>>> fdict

{'y': 2, 'x': 1}

2.fromkeys() to create a "default" dictionary with the same values for the elements

>>> ddict = {}.fromkeys(('x', 'y'), -1)

>>> ddict

{'y': -1, 'x': -1}

3. Walk through the dictionary
Traverse using keys()

>>> dict2 = {'name': 'earth', 'port': 80}

>>>

>>>> for key in dict2.keys():

... print 'key=%s, value=%s' % (key, dict2[key])

...

key=name, value=earth

key=port, value=80

Iterate through using an iterator

>>> dict2 = {'name': 'earth', 'port': 80}

>>>

>>>> for key in dict2:

... print 'key=%s, value=%s' % (key, dict2[key])

...

key=name, value=earth

key=port, value=80

4. Get the value value

The dictionary key is given in brackets

>>> dict2['name']

'earth'

5. Member operator :in or not in
Determine if the key exists

>>> 'server' in dict2 #  or  dict2.has_key('server')

False

6. Update your dictionary

>>> dict2['name'] = 'venus' #  Update existing entries 

>>> dict2['port'] = 6969 #  Update existing entries 

>>> dict2['arch'] = 'sunos5'#  Add new entries 

7. Delete the dictionary

del dict2['name']    ​# Delete key is" name The entry" 

dict2.clear()    ​# delete  dict2  All the entries in 

del dict2     ​# Delete the entire  dict2  The dictionary 

dict2.pop('name')    ​# Delete and return key is" name The entry" 

8.values() returns the list of values  

>>>

>>> dict2.values()

[80, 'earth']

9.items() returns the list of (key, value) tuples,  

>>> dict2.items()

[('port', 80), ('name', 'earth')]