change bounds of range function when it is running without stopping it

Question

if I have a python script as below:

import time
for i in range(10):
    print(i)
    time.sleep(60)

When it is running to count 3 now, is it possible to change to upper limit from 10 to 20?

To make it clear, I mean without stopping the running process. I want to change it to make it run to 20.

Say, maybe modify /dev/mem or /proc/pid/something ?

What is the exact question and how does it relate the sample code posted by you ? Please be little more descriptive. — Pralhad Narsinh Sonar, Jun 28 '15 at 17:39
@MalikBrahimi: [The documentation makes it pretty clear that it's in seconds.](https://docs.python.org/2/library/time.html#time.sleep) — user2357112, Jun 28 '15 at 18:42
Sorry, I added some on my question, I am asking if we don't stop the process, I think it is not about Python but Linux — CSJ, Jun 28 '15 at 20:23
is the question about if you can manipulate stack in python ? just as you could do in a lower level language ..say C ? — Vasif, Jun 29 '15 at 05:47
no, I mean when the process is running, can I modify anything in Linux that make `10` become `20`, so that the process can run to `20`? — CSJ, Jun 29 '15 at 06:25

Malik Brahimi · Answer 1 · 2015-06-28T18:01:01.557

1

Another name for a for loop is fixed repetition. Fixed means that you can not change constraints.

var = 0
cap = 10

while var < cap:
    var += 1
    action()

    if var == 3:
        cap = 20

edited Jun 28 '15 at 18:01

answered Jun 28 '15 at 17:46

Malik Brahimi

Where `action` is anything you wish to do, like `print` and `sleep` – Malik Brahimi Jun 28 '15 at 18:01
'can not change constraints' what does exactly mean? – Nizam Mohamed Jun 28 '15 at 19:03
@NizamMohamed `for` iterates an iterable which can not be changed during iteration. – Malik Brahimi Jun 28 '15 at 19:13
'changed' means what? insertion, removal or appending. And why? – Nizam Mohamed Jun 28 '15 at 19:16
@NizamMohamed See [here](https://unspecified.wordpress.com/2009/02/12/thou-shalt-not-modify-a-list-during-iteration/) for a great explanation. – Malik Brahimi Jun 28 '15 at 19:21
@NizamMohamed This [post](http://stackoverflow.com/questions/1637807/modifying-list-while-iterating) will help you as well. What do you think? – Malik Brahimi Jun 28 '15 at 19:24
[for loop](https://docs.python.org/2/reference/compound_stmts.html#the-for-statement) only talks about insertion and removal. Appending and extending list works ok. – Nizam Mohamed Jun 28 '15 at 20:19
Yes, appending and extending is okay, but very bad practice. It is simply inefficient compared to while loop any way for this particular purpose. – Malik Brahimi Jun 28 '15 at 20:33

score 0 · Answer 2 · edited Jan 26 '20 at 21:28

0

range returns a list in Python 2, so if it's stored which can be extended.

range_list = range(10)
for i in range_list:
    print(i)
    if i == 3:
        range_list.extend(range(10,20))
    time.sleep(60)

edited Jan 26 '20 at 21:28

Ismael Padilla

answered Jun 28 '15 at 17:39

Nizam Mohamed

I'd like to know why I got a downvote so that I can improve. – Nizam Mohamed Jun 28 '15 at 17:53
Yours only works because you're modifying at the end so the start of the list remains the same. Otherwise, changing a list while iterating is bad practice. – Malik Brahimi Jun 28 '15 at 19:28

2 Answers2