Finding 'n' Character Words in a Text File - Python

Given a text file, the task is to find all words that are exactly ‘n’ characters long. This can be useful in text analysis, data cleaning, word filtering, or pattern-matching applications.

Example: (Myfile.txt)

Hello, how are you? This is a simple text.

Input: n=3
Output: ['how', 'are', 'you']

Using Regular Expressions

Regular expressions allow you to match patterns in text efficiently. Here we can use \b\w{n}\b to find words of exact length n.

Output:

['how', 'are', 'you']

Explanation:

• text = f.read(): Reads entire file content.
• pattern = r'\b\w{n}\b': Matches words with exactly n characters (\b ensures word boundaries) (\w{n} ensure any word of length n)
• re.findall(pattern, text): Returns a list of all matching words.

Using Split and List Comprehension

This method splits text into words and filters words based on length using list comprehension.

Output:

['how', 'are', 'you']

Explanation:

• text.split(): Splits the text into words.
• [w for w in w1 if len(w) == n]: Filters words with length exactly n.

Using a Generator Function

Generators yield words one by one, making them memory-efficient for very large files.

Output:

how
are
you

Related Articles:

• Python program to read file word by word
• Count Words in Text File in Python