Python – Test Record existence in Dictionary
Sometimes while working with pool of records, we can have problem in which we need to check the presence of particular value of a key for existence. This can have application in many domains such as day-day programming or web development. Lets discuss certain ways in which this task can be performed.
Method #1 : Using any() + generator expression
The combination of above functions can be used to perform this task. In this, we simply test for all elements using any(), iterated using generator expression.
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Python3
# Python3 code to demonstrate working of# Test Record existence in Dictionary# Using any() + generator expression# initializing listtest_list = [{ 'name' : 'Nikhil', 'age' : 22}, { 'name' : 'Akshat', 'age' : 23}, { 'name' : 'Akash', 'age' : 23}]# printing original listprint("The original list is : " + str(test_list))# initializing key and valuetest_key = 'name'test_val = 'Nikhil'# Test Record existence in Dictionary# Using any() + generator expressionres = any(sub[test_key] == test_val for sub in test_list)# printing resultprint("Does key value contain in dictionary list : " + str(res)) |
The original list is : [{‘name’: ‘Nikhil’, ‘age’: 22}, {‘name’: ‘Akshat’, ‘age’: 23}, {‘name’: ‘Akash’, ‘age’: 23}]
Does key value contain in dictionary list : True
Method #2 : Using filter() + lambda
The combination of above functions can be used to perform this task. In this, we check for all values using filter and iteration using lambda function.
Python3
# Python3 code to demonstrate working of# Test Record existence in Dictionary# Using filter() + lambda# initializing listtest_list = [{ 'name' : 'Nikhil', 'age' : 22}, { 'name' : 'Akshat', 'age' : 23}, { 'name' : 'Akash', 'age' : 23}]# printing original listprint("The original list is : " + str(test_list))# initializing key and valuetest_key = 'name'test_val = 'Nikhil'# Test Record existence in Dictionary# Using filter() + lambdares = filter(lambda sub: test_val in sub.values(), test_list)if len(list(res)): res = Trueelse : res = False# printing resultprint("Does key value contain in dictionary list : " + str(res)) |
The original list is : [{‘name’: ‘Nikhil’, ‘age’: 22}, {‘name’: ‘Akshat’, ‘age’: 23}, {‘name’: ‘Akash’, ‘age’: 23}]
Does key value contain in dictionary list : True
