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Python | Count of Matching i, j index elements

  • Last Updated : 17 Dec, 2019

Sometimes, while programming, we can have a problem in which we need to check for ith and jth character of each string. We may require to extract count of all strings with similar ith and jth characters. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute force method by which this task can be performed. In this, iterate each element of list and check for each string’s ith and jth character and increase the counter in case we find a match.

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# Python3 code to demonstrate working of
# Count of Matching i, j index elements
# Using loop
  
# initialize list 
test_list = ['geeks', 'beke', 'treat', 'neke']
  
# printing original list 
print("The original list : " + str(test_list))
  
# initialize i 
i = 1
  
# initialize j 
j = 3 
  
# Count of Matching i, j index elements
# Using loop
count = 0
for ele in test_list:
    if ele[i] == ele[j]:
        count = count + 1
  
# printing result
print("Total Strings with similar ith and jth elements : " + str(count))
Output :



The original list : ['geeks', 'beke', 'treat', 'neke']
Total Strings with similar ith and jth elements : 2

 

Method #2 : Using sum() + generator expression
This is one liner alternative to perform this task. In this, we perform the task of iteration using generator expression and summation using sum().




# Python3 code to demonstrate working of
# Count of Matching i, j index elements
# Using sum() + generator expression
  
# initialize list 
test_list = ['geeks', 'beke', 'treat', 'neke']
  
# printing original list 
print("The original list : " + str(test_list))
  
# initialize i 
i = 1
  
# initialize j 
j = 3 
  
# Count of Matching i, j index elements
# Using sum() + generator expression
res = sum(1 for ele in test_list if ele[i] == ele[j])
  
# printing result
print("Total Strings with similar ith and jth elements : " + str(res))
Output :
The original list : ['geeks', 'beke', 'treat', 'neke']
Total Strings with similar ith and jth elements : 2



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