Python–提取 K 键中字符串值为空的字典
原文:https://www . geesforgeks . org/python-extract-dictionary-with-empty-string-value-in-k-key/
给定字典列表，提取所有具有空字符串作为特定键值的字典。
输入:test _ list =[{“Gfg”:“4”，“是”:“好”，“最好”:“1”}，{“Gfg”:“9”，“是”:“CS”，“最好”:“10”}]，K =“Gfg” 输出 : [] 解释:无“Gfg”键为空。
输入:test _ list =[{“Gfg”:“”、“”:“好”、“最好”:“1”}、{“Gfg”:“9”、“是”:“CS”、“最好”:“10”}]、K =“Gfg” 输出:[{“Gfg”:“”、“:“好”、“最好”:“1”}] 解释:字典中带空的“Gfg”提取出来。
方法一:使用列表理解
这是执行这项任务的方法之一。在这种情况下，我们在所有字典中运行一个循环，并检查键的空字符串值。所有这些都是在列表理解而不是循环中编译的。
Python 3
# Python3 code to demonstrate working of
# Extract dictionaries with Empty String value in K key
# Using list comprehension
# initializing lists
test_list = [{"Gfg" : "4", "is" : "good", "best" : "1"},
{"Gfg" : "", "is" : "better", "best" : "8"},
{"Gfg" : "9", "is" : "CS", "best" : "10"}]
# printing original list
print("The original list : " + str(test_list))
# initializing K key
K = "Gfg"
# using list comprehension to fetch empty string key's dictionaries
res = [sub for sub in test_list if sub[K] == '']
# printing result
print("The extracted dictionaries : " + str(res))
Output
The original list : [{'Gfg': '4', 'is': 'good', 'best': '1'}, {'Gfg': '', 'is': 'better', 'best': '8'}, {'Gfg': '9', 'is': 'CS', 'best': '10'}]
The extracted dictionaries : [{'Gfg': '', 'is': 'better', 'best': '8'}]
方法 2:使用过滤器()+λ
这是执行这项任务的另一种方式。在本文中，我们使用 filter()和 lambda 的功能和迭代提取所有空值键的字典。
Python 3
# Python3 code to demonstrate working of
# Extract dictionaries with Empty String value in K key
# Using filter() + lambda
# initializing lists
test_list = [{"Gfg" : "4", "is" : "good", "best" : "1"},
{"Gfg" : "", "is" : "better", "best" : "8"},
{"Gfg" : "9", "is" : "CS", "best" : "10"}]
# printing original list
print("The original list : " + str(test_list))
# initializing K key
K = "Gfg"
# filter() used to iteration
# lambda for functionality
res = list(filter(lambda sub: sub[K] == '', test_list))
# printing result
print("The extracted dictionaries : " + str(res))
Output
The original list : [{'Gfg': '4', 'is': 'good', 'best': '1'}, {'Gfg': '', 'is': 'better', 'best': '8'}, {'Gfg': '9', 'is': 'CS', 'best': '10'}]
The extracted dictionaries : [{'Gfg': '', 'is': 'better', 'best': '8'}]
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