Python | Split String by Length

Summary: You can split a string by length by slicing the string into chunks of equal lengths. The indices to slice the string can be deduced using a list comprehension.

Minimal Example:

text = "abcdefghijklmno"
print([text[i:i + 3] for i in range(0, len(text), 3)])

# OUTPUT: ['abc', 'def', 'ghi', 'jkl', 'mno']

Problem Formulation

📜Problem: Given a string, how will you split the string by length? Here’s a related question asked in stack overflow that perfectly demonstrates the given problem.

Related Question on StackOverflow:

Example

Consider that you have a string and you want to cut or split the string into chunks of substrings such that each substring has exactly five character. In other words each substring should have a length of five. Store each substring as an item in a list.

# Given String
text = "threeseveneightfortyfifty"
# Output
['three', 'seven', 'eight', 'forty', 'fifty']

Let’s dive into the solutions to the given problem.

Method 1: Use a List Comprehension

The best way to deal with the given problem is to use a list comprehension that splits the string with the help of slicing.

Code:

text = "threeseveneightfortyfifty"
print([text[i:i + 5] for i in range(0, len(text), 5)])

# OUTPUT: ['three', 'seven', 'eight', 'forty', 'fifty'] 

Explanation: The for loop allows you to iterate over a range of numbers that are multiples of 5 (i.e. the size of the split substrings). You can use the values returned in each iteration to slice the strings into groups of substrings having 5 characters. Please follow the illustration given below to understand how this works –

Alternate Formulation using multi-line code: The solution given above can also be formulated using a for loop in multiple lines. Here’s how to do it:

text = "threeseveneightfortyfifty"
res = []
for i in range(0, len(text), 5):
    res.append(text[i:i + 5])
print(res)

# OUTPUT: ['three', 'seven', 'eight', 'forty', 'fifty']

Method 2: Use textwrap

Another workaround to solve the problem is to use the textwrap library’s fill(text, width) function, which allows you to wrap a string into equal width. This means the given string will be split (wrapped, to be exact) into numerous substrings of equal length/width. The output returned is a string object. Hence, you need to convert it to a list by using a normal split function.

Code:

import textwrap

text = "threeseveneightfortyfifty"
x = textwrap.fill(text, 5).split()
print(x)

# OUTPUT: ['three', 'seven', 'eight', 'forty', 'fifty'] 

Method 3: Use regex

The regular expressions library leverages numerous functions to split a string in any given way. In this case, you can use the compile function of the regex library to solve the given problem.

Code:

import re
text = "threeseveneightfortyfifty"
sre = re.compile(rf'(.{{{5}}})')
print([x for x in re.split(sre, text) if x])

# OUTPUT: ['three', 'seven', 'eight', 'forty', 'fifty'] 

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Method 4: Use a Generator

Another workaround to solve the problem is to use the yield keyword that creates a generator object and returns the split substrings one by one as items in a list.

Code:

def split_len(s, n):
    def _f(s, n):
        while s:
            yield s[:n]
            s = s[n:]
    return list(_f(s, n))

text = "threeseveneightfortyfifty"
chunks = 5
print(split_len(text, chunks))

# OUTPUT: ['three', 'seven', 'eight', 'forty', 'fifty'] 

🌎Recommended Read: Yield Keyword in Python – A Simple Illustrated Guide

Conclusion

We have successfully solved the given problem using different approaches. I hope this article helped you in your Python coding journey. Please subscribe and stay tuned for more interesting articles and solutions.

Happy Coding! 🙂

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