Python Write lines of a text in between a range of numbers to a new file

Question

Sample Text File:

1. some text here
2. more text here
more text here
more text here
more text here
3. more text here
more text here
more text here
more text here
4. more text here
more text here
more text here
more text here
5. more text here
more text here
more text here
more text here
6. last text here
more text here
more text here
more text here

1. new text here
more text here
more text here
2. some more text
more text here
3. a bit more text
more text here
4. ok this is enough text.

1. nawww heres a bit more text.
more text here
more text here
2. okay this is the final text.
more text here
more text here
3. just to be sure this is last.
more text here
1. etc

This is a sample text from what I have, but this is a lot shorter.

I have this python code as a start:

with open("text.txt") as txt_file:
    lines = txt_file.readlines()
    for line in lines:
        if line.startswith('1.'):
            print(line)

But I am stuck with the fact that I have no idea how to print all the lines after the 1., to the next 1. into a separate file

I'm assuming that I'd have to have some sort of for loop in the last if statement I have there, but i'm not sure how to go about doing that.

For an example of what I expect my results to be is this:

If a line starts with 1.. Write the text and after that into a new text file until the next line that starts with 1., then start the whole process over again until there is no more text. So I for the sample text above I should have 4 files.

In this case file number 1. would have all text from the paragraphs from 1-6.

1. some text here
2. more text here
more text here
more text here
more text here
3. more text here
more text here
more text here
more text here
4. more text here
more text here
more text here
more text here
5. more text here
more text here
more text here
more text here
6. last text here
more text here
more text here
more text here

File number 2. would have all the text from the second 1. in the sample text file from all paragraphs 1-4

1. new text here
more text here
more text here
2. some more text
more text here
3. a bit more text
more text here
4. ok this is enough text.

File number 3. would have all the text from the third 1. in the sample text file from all paragraphs from 1-3

1. nawww heres a bit more text.
more text here
more text here
2. okay this is the final text.
more text here
more text here
3. just to be sure this is last.
more text here

And so one...

I hope i'm explaining this right and in a way that makes sense.

Answer 1

Here's another solution. You can tweak this as you see fit, but I found the index of all lines that contained 1. then just wrote the lines in between those indexes to new files.

with open('test.txt') as f:
    lines = f.readlines()
    ones_index = []
    for idx, line in enumerate(lines):
        if '1.' in line:
            ones_index.append(idx)

    ones_index[len(lines):] = [len(lines)]

    for i in range(len(ones_index)-1):
        start = ones_index[i]
        stop = ones_index[i+1]
        with open('newfile-{}.txt'.format(i), 'w') as g:
            g.write('\n'.join(lines[start:stop]))

Edit: I just realized this didn't handle the very last range of lines at first. Added a new line to fix this.