Given a list of dictionary, the task is to sort the dictionary by date. Let’s see a few methods to solve the task.
Method #1: Using naive approach
# Python code to demonstrate # sort a list of dictionary # where value date is in string # Initialising list of dictionary ini_list = [{'name':'akash', 'd.o.b':'1997-03-02'}, {'name':'manjeet', 'd.o.b':'1997-01-04'}, {'name':'nikhil', 'd.o.b':'1997-09-13'}] # printing initial list print ("initial list : ", str(ini_list)) # code to sort list on date ini_list.sort(key = lambda x:x['d.o.b']) # printing final list print ("result", str(ini_list)) |
initial list : [{‘name’: ‘akash’, ‘d.o.b’: ‘1997-03-02’}, {‘name’: ‘manjeet’, ‘d.o.b’: ‘1997-01-04’}, {‘name’: ‘nikhil’, ‘d.o.b’: ‘1997-09-13’}]
result [{‘name’: ‘manjeet’, ‘d.o.b’: ‘1997-01-04’}, {‘name’: ‘akash’, ‘d.o.b’: ‘1997-03-02’}, {‘name’: ‘nikhil’, ‘d.o.b’: ‘1997-09-13’}]
Method #2: Using datetime.strptime and lambda
# Python code to demonstrate # sort a list of dictionary # where value date is in a string from datetime import datetime # Initialising list of dictionary ini_list = [{'name':'akshat', 'd.o.b':'1997-09-01'}, {'name':'vashu', 'd.o.b':'1997-08-19'}, {'name':'manjeet', 'd.o.b':'1997-01-04'}, {'name':'nikhil', 'd.o.b':'1997-09-13'}] # printing initial list print ("initial list : ", str(ini_list)) # code to sort list on date ini_list.sort(key = lambda x: datetime.strptime(x['d.o.b'], '%Y-%m-%d')) # printing final list print ("result", str(ini_list)) |
initial list : [{‘d.o.b’: ‘1997-09-01’, ‘name’: ‘akshat’}, {‘d.o.b’: ‘1997-08-19’, ‘name’: ‘vashu’}, {‘d.o.b’: ‘1997-01-04’, ‘name’: ‘manjeet’}, {‘d.o.b’: ‘1997-09-13’, ‘name’: ‘nikhil’}]
result [{‘d.o.b’: ‘1997-01-04’, ‘name’: ‘manjeet’}, {‘d.o.b’: ‘1997-08-19’, ‘name’: ‘vashu’}, {‘d.o.b’: ‘1997-09-01’, ‘name’: ‘akshat’}, {‘d.o.b’: ‘1997-09-13’, ‘name’: ‘nikhil’}]
Method #3: Using operator.itemgetter
# Python code to demonstrate # sort a list of dictionary # where value date is in string import operator # Initialising list of dictionary ini_list = [{'name':'akash', 'd.o.b':'1997-03-02'}, {'name':'manjeet', 'd.o.b':'1997-01-04'}, {'name':'nikhil', 'd.o.b':'1997-09-13'}] # printing initial list print ("initial list : ", str(ini_list)) # code to sort list on date ini_list.sort(key = operator.itemgetter('d.o.b')) # printing final list print ("result", str(ini_list)) |
initial list : [{‘d.o.b’: ‘1997-03-02’, ‘name’: ‘akash’}, {‘d.o.b’: ‘1997-01-04’, ‘name’: ‘manjeet’}, {‘d.o.b’: ‘1997-09-13’, ‘name’: ‘nikhil’}]
result [{‘d.o.b’: ‘1997-01-04’, ‘name’: ‘manjeet’}, {‘d.o.b’: ‘1997-03-02’, ‘name’: ‘akash’}, {‘d.o.b’: ‘1997-09-13’, ‘name’: ‘nikhil’}]
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