A Dictionary of Python learning

1. Creating and Using dictionaries
1) format of the dictionary:
Phonebook = {' Alice ': ' 1234 ', ' Beth ': ' 1920x1080 ', ' Cecil ': ' 4537 '}
The ====== dictionary consists of two curly braces, separated by a colon: between the key and the value, separated by commas.

2) Create a dictionary--dict function:
Dict (), New Empty dictionary.
>>> items = [(' Name ', ' Sandy '), (' age ', 38)]
>>> d = dict (items)
>>> D
{' Age ': $, ' name ': ' Sandy '}
>>> d[' name ']
' Sandy '
>>>
>>> Dict ()
{}
>>> dict (name= ' Sandy ', age=42)
{' Age ':, ' name ': ' Sandy '}
>>> Dict (sandy=38,alice=32)
{' Alice ': +, ' Sandy ': 38}
>>>

3) Basic operation of the dictionary
Len (d)---Returns the number of items in the dictionary;
D[K]---Returns the value of the key k;
D[K]=V---Associates the value to the key k;
Del D[k]---Delete the key to K;
K in d---check D for items with key K

2. Dictionary method

Method	Role	return value	Use
Clear	Clears all items in the dictionary	None (no return value)	D.clear ()
Copy	Copy Dictionary	Returns a new dictionary with the same item	X=d.copy ()
Fromkeys	Creates a new dictionary with the given key, with the default corresponding value of None for each key	A new dictionary?
Get	Access to a dictionary item by key is more lenient than direct access (such as d[' name '), which returns none when attempting to access a nonexistent item	Value or None	D.get (' name ')
Has_key	Check if the dictionary contains the given key, which is the equivalent of K in D	True or False	D.haskey (k)
Items and Iteritems	Items returns a list of all items in the dictionary	List	D.items ()
Keys and Iterkeys	The Keys method returns the key of the dictionary as a list	List	D.key ()
Pop	Gets the value corresponding to the given key and removes the key-value from the dictionary	Value	D.pop ()
Values	Returns the value of the dictionary as a list	List	D.values ()
SetDefault	Gets the value associated with the given key and, if the key does not exist, sets the key and the default value (given or none) in the dictionary	Value or key-value	D.setdefault (' name ', ' N/A ')
Update	Update another dictionary with one dictionary item	Updated dictionaries	D.update (x)

A Dictionary of Python learning