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Python | Counting Nth tuple element

  • Last Updated : 03 Nov, 2019

Sometimes, while working with Python, we can have a problem in which we need to count the occurrence of a particular’s elements. This kind of problem is quite common while working with records. Let’s discuss a way in which this task can be performed.

Method #1 : Using Counter() + generator expression
The combination of above functionalities can be used to achieve this particular task. In this, we iterate through a specific index using generator expression and compute the count using Counter().




# Python3 code to demonstrate working of
# Counting Nth tuple element
# using Counter() + generator expression
from collections import Counter
  
# initialize list
test_list = [('gfg', 0), ('is', 1), ('best', 2),
             ('gfg', 2), ('is', 0), ('for', 1),
             ('geeks', 2)]
  
# printing original list
print("The original list : " + str(test_list))
  
# initialize N
N = 1
  
# Counting Nth tuple element
# using Counter() + generator expression
res = dict(Counter(sub[N] for sub in test_list))
  
# printing result
print("The grouped Nth element frequency is : " + str(res))
Output :

The original list : [(‘gfg’, 0), (‘is’, 1), (‘best’, 2), (‘gfg’, 2), (‘is’, 0), (‘for’, 1), (‘geeks’, 2)]
The grouped Nth element frequency is : {0: 2, 1: 2, 2: 3}

 



Method #2 : Using Counter() + map() + itemgetter()
The combination of above functions can be used to achieve this task. In this, the task performed by generator expression is performed by map() and itemgetter() is used to get the index of the container element.




# Python3 code to demonstrate working of
# Counting Nth tuple element
# using Counter() + map() + itemgetter()
from collections import Counter
from operator import itemgetter
  
# initialize list
test_list = [('gfg', 0), ('is', 1), ('best', 2), 
             ('gfg', 2), ('is', 0), ('for', 1),
             ('geeks', 2)]
  
# printing original list
print("The original list : " + str(test_list))
  
# initialize N
N = 1
  
# Counting Nth tuple element
# using Counter() + map() + itemgetter()
res = dict(Counter(map(itemgetter(N), test_list)))
  
# printing result
print("The grouped Nth element frequency is : " + str(res))
Output :

The original list : [(‘gfg’, 0), (‘is’, 1), (‘best’, 2), (‘gfg’, 2), (‘is’, 0), (‘for’, 1), (‘geeks’, 2)]
The grouped Nth element frequency is : {0: 2, 1: 2, 2: 3}

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