在Python中向字典添加键：值对

Python中的字典是数据值的无序集合，用于像地图一样存储数据值，与其他仅将单个值作为元素保存的数据类型不同，字典包含键：值对。

在使用字典时，有时我们需要在字典中添加或修改键/值。让我们看看如何在Python中将key:value对添加到字典中。

代码 #1：使用下标符号

此方法将通过为该键分配一个值来在字典上创建一个新的键：值对。

# Python program to add a key:value pair to dictionary
  
dict = {'key1':'geeks', 'key2':'for'} 
print("Current Dict is: ", dict) 
    
# using the subscript notation 
# Dictionary_Name[New_Key_Name] = New_Key_Value 
  
dict['key3'] = 'Geeks'
dict['key4'] = 'is'
dict['key5'] = 'portal'
dict['key6'] = 'Computer'
print("Updated Dict is: ", dict)

输出：

Current Dict is: {‘key2’: ‘for’, ‘key1’: ‘geeks’}
Updated Dict is: {‘key3’: ‘Geeks’, ‘key5’: ‘portal’, ‘key6’: ‘Computer’, ‘key4’: ‘is’, ‘key1’: ‘geeks’, ‘key2’: ‘for’}

代码 #2：使用 update() 方法

dict = {'key1':'geeks', 'key2':'for'} 
print("Current Dict is: ", dict) 
  
# adding dict1 (key3, key4 and key5) to dict 
dict1 = {'key3':'geeks', 'key4':'is', 'key5':'fabulous'} 
dict.update(dict1) 
  
# by assigning 
dict.update(newkey1 ='portal') 
print(dict) 

输出：

Current Dict is: {‘key2’: ‘for’, ‘key1’: ‘geeks’}
{‘newkey1’: ‘portal’, ‘key4’: ‘is’, ‘key2’: ‘for’, ‘key1’: ‘geeks’, ‘key5’: ‘fabulous’, ‘key3’: ‘geeks’}

代码 #3：以 Key:value 作为输入

# Let's add key:value to a dictionary, the functional way 
  
# Create your dictionary class 
class my_dictionary(dict): 
  
    # __init__ function 
    def __init__(self): 
        self = dict() 
          
    # Function to add key:value 
    def add(self, key, value): 
        self[key] = value 
  
# Main Function 
dict_obj = my_dictionary() 
  
# Taking input key = 1, value = Geek
dict_obj.key = input("Enter the key: ")
dict_obj.value = input("Enter the value: ")
  
dict_obj.add(dict_obj.key, dict_obj.value) 
dict_obj.add(2, 'forGeeks') 
  
print(dict_obj) 

输出：

{'1': 'Geeks', 2: 'forGeeks'}