Python – Bigrams Frequency in String

• Last Updated : 08 May, 2020

Sometimes while working with Python Data, we can have problem in which we need to extract bigrams from string. This has application in NLP domains. But sometimes, we need to compute the frequency of unique bigram for data collection. The solution to this problem can be useful. Lets discuss certain ways in which this task can be performed.

Method #1 : Using Counter() + generator expression
The combination of above functions can be used to solve this problem. In this, we compute the frequency using Counter() and bigram computation using generator expression and string slicing.

 # Python3 code to demonstrate working of # Bigrams Frequency in String# Using Counter() + generator expressionfrom collections import Counter      # initializing stringtest_str = 'geeksforgeeks'  # printing original stringprint("The original string is : " + str(test_str))  # Bigrams Frequency in String# Using Counter() + generator expressionres = Counter(test_str[idx : idx + 2] for idx in range(len(test_str) - 1))  # printing result print("The Bigrams Frequency is : " + str(dict(res)))
Output :

The original string is : geeksforgeeks
The Bigrams Frequency is : {‘ee’: 2, ‘ks’: 2, ‘ek’: 2, ‘sf’: 1, ‘fo’: 1, ‘ge’: 2, ‘rg’: 1, ‘or’: 1}

Method #2 : Using Counter() + zip() + map() + join
The combination of above functions can also be used to solve this problem. In this, we perform the task of constructing bigrams using zip() + map() + join.

 # Python3 code to demonstrate working of # Bigrams Frequency in String# Using Counter() + zip() + map() + joinfrom collections import Counter      # initializing stringtest_str = 'geeksforgeeks'  # printing original stringprint("The original string is : " + str(test_str))  # Bigrams Frequency in String# Using Counter() + zip() + map() + joinres = Counter(map(''.join, zip(test_str, test_str[1:])))  # printing result print("The Bigrams Frequency is : " + str(dict(res)))
Output :

The original string is : geeksforgeeks
The Bigrams Frequency is : {‘ee’: 2, ‘ks’: 2, ‘ek’: 2, ‘sf’: 1, ‘fo’: 1, ‘ge’: 2, ‘rg’: 1, ‘or’: 1}

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