Python Dictionary（字典）进阶内容

两个字典嵌套，字典2初始化为空字典，在遍历字典1的过程中增加字典2的内容

A = [1,2,3]
B = [4,5,6]

dic1 = {'A':A,'B':B}
dic2 = {}
print("dic1: ",dic1)
i =0

for key,val in dic1.items():
    dic2[key+'_Mask'] = i
    i =i+1
print("dic2: ",dic2)
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输出：

dic1:  {'A': [1, 2, 3], 'B': [4, 5, 6]}
dic2:  {'A_Mask': 0, 'B_Mask': 1}
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这种方法适合基于一个字典（keys）生成另外一个字典。

单空字典，是否可以从空字典开始循环增加内容，NO!

dic2 = {}
for key,val in dic2.items():
    dic2[key+'_Mask'] = i
    i =i+1
print("dic2: ",dic2)
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输出：

dic2:  {}

Process finished with exit code 0
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单非空字典，是否可以循环增加内容，NO！

A = [1,2,3]
B = [4,5,6]

dic = {'A':A,'B':B}
print("dic: ",dic)
i =0

for key,val in dic.items():
    dic[key+'_Mask'] = i
    i =i+1
print("dic: ",dic)
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报错如下

dic1:  {'A': [1, 2, 3], 'B': [4, 5, 6]}
Traceback (most recent call last):
  File "Test0818.py", line 11, in <module>
    for key,val in dic.items():
RuntimeError: dictionary changed size during iteration
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单非空字典，增加list（）就行

A = [1,2,3]
B = [4,5,6]

dic = {'A':A,'B':B}
print("dic: ",dic)
i =0

for key,val in list(dic.items()):
    dic[key+'_Mask'] = i
    i =i+1
print("dic1: ",dic)
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输出

dic:  {'A': [1, 2, 3], 'B': [4, 5, 6]}
dic1:  {'A': [1, 2, 3], 'B': [4, 5, 6], 'A_Mask': 0, 'B_Mask': 1}
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单非空字典，是否可以循环删除内容，NO！

A = [1,2,3]
B = [4,5,6]

dic = {'A':A,'B':B}
i =0

for key,val in dic.items():
    print("dic: ", dic)
    del dic[key]
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报错：

dic:  {'A': [1, 2, 3], 'B': [4, 5, 6]}
Traceback (most recent call last):
  File "Test0818.py", line 10, in <module>
    for key,val in dic.items():
RuntimeError: dictionary changed size during iteration
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单非空字典，增加list（）可循环删除内容

A = [1,2,3]
B = [4,5,6]

dic = {'A':A,'B':B}
i =0

for key,val in list(dic.items()):
    print("dic1: ", dic)
    del dic[key]
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输出：

dic1:  {'A': [1, 2, 3], 'B': [4, 5, 6]}
dic1:  {'B': [4, 5, 6]}
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不遍历，直接增加字典内容

A = [1,2,3]
B = [4,5,6]

dic = {'A':A,'B':B}
print("dic: ",dic)
dic['C']=1
print("dic: ",dic)
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输出：

dic:  {'A': [1, 2, 3], 'B': [4, 5, 6]}
dic:  {'A': [1, 2, 3], 'B': [4, 5, 6], 'C': 1}

Process finished with exit code 0
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通过循环创建字典

dicts = {}

keys = [10, 12, 14, 16]
values = ["A", "B", "C", "D"]

for i in range(len(keys)):
    dicts[keys[i]] = values[i]
print(dicts)
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