Python 程序：檢查字典中是否存在給定鍵

寫一個 Python 程序，用一個實際例子來檢查字典中是否存在給定的鍵。

檢查字典中是否存在給定鍵的 Python 程序示例 1

在這個 python 程序中，我們使用 if 語句和鍵功能來檢查該鍵是否存在於這個字典中。如果為真，則打印鍵值。

# Python Program to check if a Given key exists in a Dictionary

myDict = {'a': 'apple', 'b': 'Banana' , 'o': 'Orange', 'm': 'Mango'}
print("Dictionary : ", myDict)

key = input("Please enter the Key you want to search for: ")

# Check Whether the Given key exists in a Dictionary or Not
if key in myDict.keys():
    print("\nKey Exists in this Dictionary")
    print("Key = ", key, " and Value = ", myDict[key])
else:
    print("\nKey Does not Exists in this Dictionary")

Python 程序驗證給定的鍵是否存在於字典中示例 2

這個 Python 程序是檢查給定鍵是否存在於字典中的另一種方法。

myDict = {'a': 'apple', 'b': 'Banana' , 'o': 'Orange', 'm': 'Mango'}
print("Dictionary : ", myDict)

key = input("Please enter the Key you want to search for: ")

# Check Whether the Given key exists in a Dictionary or Not
if key in myDict:
    print("\nKey Exists in this Dictionary")
    print("Key = ", key, " and Value = ", myDict[key])
else:
    print("\nKey Does not Exists in this Dictionary")

Dictionary :  {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'm': 'Mango'}
Please enter the Key you want to search for: m

Key Exists in this Dictionary
Key =  m  and Value =  Mango
>>> 
Dictionary :  {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'm': 'Mango'}
Please enter the Key you want to search for: g

Key Does not Exists in this Dictionary
>>> 

檢查字典中是否存在鍵的 Python 程序示例 3

在這個 python 程序中，我們使用 get 函數來檢查密鑰是否存在。

myDict = {'a': 'apple', 'b': 'Banana' , 'o': 'Orange', 'm': 'Mango'}
print("Dictionary : ", myDict)

key = input("Please enter the Key you want to search for: ")

# Check Whether the Given key exists in a Dictionary or Not
if myDict.get(key) != None:
    print("\nKey Exists in this Dictionary")
    print("Key = ", key, " and Value = ", myDict[key])
else:
    print("\nKey Does not Exists in this Dictionary")

Dictionary :  {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'm': 'Mango'}
Please enter the Key you want to search for: a

Key Exists in this Dictionary
Key =  a  and Value =  apple
>>> 
Dictionary :  {'a': 'apple', 'b': 'Banana', 'o': 'Orange', 'm': 'Mango'}
Please enter the Key you want to search for: x

Key Does not Exists in this Dictionary
>>>