python dict type like json-白红宇

python的dictionary类型和JSON类似,

定义dict类型的方法: 使用{}构造符或dict()

>>> new_dict={}

>>> type(new_dict)

>>> new_dict2=dict()

>>> type(new_dict2)

如下 :

>>> new_dict1={"a":"hello", "b":[1,2,3,4,5]}

>>> print(new_dict1)

{'a': 'hello', 'b': [1, 2, 3, 4, 5]}

甚至还可以嵌套

>>> new_dict3={"hello":new_dict2,"a":"b"}

>>> print(new_dict3)

{'hello': {}, 'a': 'b'}

>>> new_dict2=new_dict3

>>> print(new_dict3)

{'hello': {}, 'a': 'b'}

>>> new_dict2={"www":"sky-mobi"}

>>> print(new_dict3)

{'hello': {}, 'a': 'b'}

[其他]

list的用法举例, pop用于取出最后一个值, FILO的方式取数据.

>>> new_l1=[1,2,3,4,5,6]

>>> new_l1.pop()

>>> new_l1

[1, 2, 3]

扩展单个元素使用append

>>> new_l1.append(4)

>>> new_l1.pop()

扩展多个元素使用extend

>>> new_l1.extend([4,5,6,7])

>>> new_l1.pop()

>>> new_l1

[1, 2, 3, 4, 5, 6]

按位置插入使用insert

>>> new_l1.insert(1,10)

>>> new_l1

[1, 10, 2, 3, 4, 5, 6]

直接倒序, 使用reverse

>>> new_l1.reverse()

>>> new_l1

[6, 5, 4, 3, 2, 10, 1]

按index位置取数据

>>> new_l1.pop(1)

清除使用remove(x)或clear()

Operation	Result	Notes
s[i] = x	item i of s is replaced by x
s[i:j] = t	slice of s from i to j is replaced by the contents of the iterable t
del s[i:j]	same as s[i:j] = []
s[i:j:k] = t	the elements of s[i:j:k] are replaced by those of t	(1)
del s[i:j:k]	removes the elements of s[i:j:k] from the list
s.append(x)	appends x to the end of the sequence (same ass[len(s):len(s)] = [x])
s.clear()	removes all items from s (same as del s[:])	(5)
s.copy()	creates a shallow copy of s (same as s[:])	(5)
s.extend(t)	extends s with the contents of t (same ass[len(s):len(s)] = t)
s.insert(i, x)	inserts x into s at the index given by i (same as s[i:i] =[x])
s.pop([i])	retrieves the item at i and also removes it from s	(2)
s.remove(x)	remove the first item from s where s[i] == x	(3)
s.reverse()	reverses the items of s in place	(4)

Notes:

t must have the same length as the slice it is replacing.

The optional argument i defaults to -1, so that by default the last item is removed and returned.

remove raises when x is not found in s.

The reverse() method modifies the sequence in place for economy of space when reversing a large sequence. To remind users that it operates by side effect, it does not return the reversed sequence.

clear() and copy() are included for consistency with the interfaces of mutable containers that don’t support slicing operations (such as and)

New in version 3.3: clear() and copy() methods.