Python | Dictionary has _ key()
Python 中的 Dictionary 是一个无序的数据值集合，用于像地图一样存储数据值，与其他只保存单个值作为元素的数据类型不同，Dictionary 保存 key : value 对。
在 Python 字典中， has_key() 方法返回 true 如果字典中存在指定的键，否则返回 false。
语法:dict . has _ key(key) T3】参数:
- 键–这是要在字典中搜索的键。
返回:如果给定的键在字典中可用，方法返回真，否则返回假。
示例#1:
计算机编程语言
# Python program to show working
# of has_key() method in Dictionary
# Dictionary with three items
Dictionary1 = {'A': 'Geeks', 'B': 'For', 'C': 'Geeks'}
# Dictionary to be checked
print("Dictionary to be checked: ")
print(Dictionary1)
# Use of has_key() to check
# for presence of a key in Dictionary
print(Dictionary1.has_key('A'))
print(Dictionary1.has_key('For'))
输出:
Dictionary to be checked:
{'A': 'Geeks', 'C': 'Geeks', 'B': 'For'}
True
False
例 2:
计算机编程语言
# Python program to show working
# of has_key() method in Dictionary
# Dictionary with three items
Dictionary2 = {1: 'Welcome', 2: 'To', 3: 'Geeks'}
# Dictionary to be checked
print("Dictionary to be checked: ")
print(Dictionary2)
# Use of has_key() to check
# for presence of a key in Dictionary
print(Dictionary2.has_key(1))
print(Dictionary2.has_key('To'))
输出:
Dictionary to be checked:
{1: 'Welcome', 2: 'To', 3: 'Geeks'}
True
False
注意: dict.has_key()已经从 Python 3.x 中移除
has_key()在 Python 3 中已被删除。运算符 中的 用于检查字典中是否存在指定的键。
示例:
Python 3
# Python Program to search a key in Dictionary
# Using in operator
dictionary = {1: "Geeks", 2: "For", 3: "Geeks"}
print("Dictionary: {}".format(dictionary))
# Return True if Present.
if 1 in dictionary: # or "dictionary.keys()"
print(dictionary[1])
else:
print("{} is Absent".format(1))
# Return False if not Present.
if 5 in dictionary.keys():
print(dictionary[5])
else:
print("{} is Absent".format(5))
输出:
Dictionary: {1:"Geeks",2:"For",3:"Geeks"}
Geeks
5 is Absent
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