Python 字典更新()方法
原文:https://www . geesforgeks . org/python-dictionary-update-method/
Python Dictionary update()方法使用另一个字典对象或一组键/值对中的元素更新字典。
语法:dict . update([其他])
参数:该方法以字典或键/值对(一般为元组)的可迭代对象作为参数。
返回:它不返回任何值，但使用字典对象或键/值对的可迭代对象中的元素更新字典。
Python 词典更新()示例
示例#1: 用另一个字典更新
Python 3
# Python program to show working
# of update() method in Dictionary
# Dictionary with three items
Dictionary1 = {'A': 'Geeks', 'B': 'For', }
Dictionary2 = {'B': 'Geeks'}
# Dictionary before Updation
print("Original Dictionary:")
print(Dictionary1)
# update the value of key 'B'
Dictionary1.update(Dictionary2)
print("Dictionary after updation:")
print(Dictionary1)
输出:
Original Dictionary:
{'A': 'Geeks', 'B': 'For'}
Dictionary after updation:
{'A': 'Geeks', 'B': 'Geeks'}
示例#2: 使用可迭代更新
Python 3
# Python program to show working
# of update() method in Dictionary
# Dictionary with single item
Dictionary1 = {'A': 'Geeks'}
# Dictionary before Updation
print("Original Dictionary:")
print(Dictionary1)
# update the Dictionary with iterable
Dictionary1.update(B='For', C='Geeks')
print("Dictionary after updation:")
print(Dictionary1)
输出:
Original Dictionary:
{'A': 'Geeks'}
Dictionary after updation:
{'C': 'Geeks', 'B': 'For', 'A': 'Geeks'}
示例#3:如果键存在，Python 字典更新值
Python 3
def checkKey(dict, key):
if key in dict.keys():
print("Key exist, ", end =" ")
dict.update({'m':600})
print("value updated =", 600)
else:
print("Not Exist")
dict = {'m': 700, 'n':100, 't':500}
key = 'm'
checkKey(dict, key)
print(dict)
输出:
Key exist, value updated = 600
{'m': 600, 'n': 100, 't': 500}
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