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字典常用语法

时间:2017-02-14 21:53:44      阅读:242      评论:0      收藏:0      [点我收藏+]

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1. 创建字典

描述:生成字典

语法:

dic={k1:v1}

样例:

技术分享
dic=dict(k1=v1,k2=v2)

dic={k1:v1,k2:v2}
View Code

2. 取键值get

描述:取键值,若字典中没有键,则输出自定义字段,默认为none

语法:

    def get(self, k, d=None): # real signature unknown; restored from __doc__
        """ D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None. """
        pass

样例:

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dic={k1:v1,k2:v2}
a=dic.get(k1)
v1
c=dic.get(k3)
none    #字典中无该键,显示none
c=dic.get(k3,no)  
no   #字典中无该键,显示no
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3. 取键的值

描述:取字典中的键

语法:

 def keys(self): # real signature unknown; restored from __doc__
        """ D.keys() -> a set-like object providing a view on D‘s keys """
        pass

样例:

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dic=dict(k1=v1,k2=v2)
dic.keys()
for k in dic.keys():
    print(k)

result:k1, k2  #显示结果
View Code  

4. 取键值

描述:取字典中的键值

语法:

   def values(self): # real signature unknown; restored from __doc__
        """ D.values() -> an object providing a view on D‘s values """
        pass

样例:

技术分享
dic=dict(k1=v1,k2=v2)
for v in dic.values():
    print(v)

v=v1,v2 #结果
View Code

5. 取键值对的值  

描述:取字典中的键值对

语法:

    def items(self): # real signature unknown; restored from __doc__
        """ D.items() -> a set-like object providing a view on D‘s items """
        pass

样例:

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dic={k1:v1,k2:v2}

for k,v in dic.items():
    print(k,v)

#结果
k1 v1
k2 v2   
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6. 删除键值对  

描述:删除字典中的键

语法:

 def pop(self, k, d=None): # real signature unknown; restored from __doc__
        """
        D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
        If key is not found, d is returned if given, otherwise KeyError is raised
        """
        pass

样例:

技术分享
dic=dict(k1=v1,k2=v2,k3=v3)
dic.pop(k2)
print(dic)

dic={k3: v3, k1: v1}  #结果
View Code

7. 更新键值对  

描述:更新字典中的键

语法:

   def update(self, E=None, **F): # known special case of dict.update
        """
        D.update([E, ]**F) -> None.  Update D from dict/iterable E and F.
        If E is present and has a .keys() method, then does:  for k in E: D[k] = E[k]
        If E is present and lacks a .keys() method, then does:  for k, v in E: D[k] = v
        In either case, this is followed by: for k in F:  D[k] = F[k]
        """
        pass

样例:

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dic=dict(k1=v1,k2=v2,k3=v3)
dic.update({k4:v4})
print(dic)

dic={k4: v4, k3: v3, k1: v1, k2: v2} #结果
View Code

8. 更新键值  

描述:更新字典中的键

语法:

dict[key]=value  

样例:

技术分享
dic=dict(k1=v1,k2=v2,k3=v3)
dic[k1]=1
print(dic)

dic={k3: v3, k1: 1, k2: v2}  #结果
View Code

 

  

 

字典常用语法

标签:.com   self   and   src   ima   upd   res   elf   store   

原文地址:http://www.cnblogs.com/xujianghua/p/6399312.html

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