循环遍历文本文件中固定数量的字符

Question

Let's say that I have a file.txt with consecutive characters (no spaces nor newlines), like this:

ABCDHELOABCDFOOOABCD

And I want to loop through the file, iterating through fixed amounts of 4 characters, like this:

[ABCD, HELO, ABCD, FOOO, ABCD] 

A regular loop won't do: how can I achieve this?

Answer 1

You can read four characters from the file at a time, by using TextIOWrapper.read 's optional size parameter. Here I'm using Python 3.8's "walrus" operator, but it's not strictly required:

with open("file.txt", "r") as file:
    while chunk := file.read(4):
        print(chunk)

Answer 2

Assuming that you've read the input of your file and converted the entire chunk into a single string called data, you could iterate over it like so:

individual_strings = data[::4]

This gives you a list of strings as required which you can then loop over!

Answer 3

try this:

with open('file.txt', 'r') as f:
   content = f.read()
   splited_by_four_letters = [content[i:i+4] for i in range(len(content))]
   // do whatever you want with your data here

Answer 4

A simple loop like this would work. Not very pythonic, but gets the job done

s = 'ABCDHELLOABCDFOOOABCD'
for i in range(0,len(s),3):
    print(s[i:i+3])

Answer 5

There is built-in textwrap module which has wrap function. So one can accomplish tasks without loop this way:

import textwrap

with open('file.txt', 'r') as f:
    chunked = textwrap.wrap(f.read(), 4)

# chunked -> ['ABCD', 'HELO', 'ABCD', 'FOOO', 'ABCD']