Fourth Chapter: Dictionary

The dictionary is the only built-in mapping type in Python; its keys can be numbers, strings, or tuples;

The key and value are separated by a colon and a comma between the items;

(1) Dict (List of tuples)!!! ), or constructed by means of a key= value, (2) Len (d), D[k],del D[k], k in d//K;

(3) about the format output of the dictionary, "Ceil's phone number is% (ceil) s."% xxxx set the key to the value!

(4) Clear () deletes the data, not the index. (5) Copy is still not clear, need processing!!

(6) Fromkeys ([xx,xx]); Creates a key-value pair with the given key. (7) Get (key), used instead of direct access to the problem, in the absence of a corresponding key, you can easily return to none, or the specified key.

(8) D.has_key (k) equivalent to K in D (9) Item, returns the list of corresponding tuples

(ten) Pop (' key ') (one) Popitem will return a random item in a tuple (a) SetDefault when there is no stored key, value, press the key value, if the key has a value without modification, similar to the Get method;

Update updates another dictionary with one dictionary

Fourth Chapter: Dictionary