Randomly change the prompt in the Python interpreter

Question

It's kind of boring to always see the >>> prompt in Python. What would be the best way to go about randomly changing the prompt prefix?

I imagine an interaction like:

This is a tobbaconist!>> import sys
Sorry?>> import math
Sorry?>> print sys.ps1
Sorry?
What?>>

Answer 1

According to the docs, if you assign a non-string object to sys.ps1 then it will evaluate the str function of it each time:

If a non-string object is assigned to either variable, its str() is re-evaluated each time the interpreter prepares to read a new interactive command; this can be used to implement a dynamic prompt.

Well now it's obvious, you should make it dynamic! Make an object with a __str__ method where you can place any logic you want:

class Prompt:
    def __str__(self):
        # Logic to randomly determine string
        return string

You can also make changes or insert things into this class as you go too. So for example, you could have a list of messages in Prompt that you append to, or change, and that will affect the console message.

Answer 2

Try this:

>>> import sys
>>> import random
>>> class RandomPrompt(object):
...     prompts = 'hello >', 'hi >', 'hey >'
...     def __repr__ (self): return random.choice(self.prompts)
... 
>>> sys.ps1 = RandomPrompt()
hello >1
1
hi >2
2

Answer 3

For changing the prompt, we use

>>>import sys
>>>sys.ps1 = '=>'
=>

Now the way to do it randomly would be something like this:

import random
import sys

random_prompts = ['->', '-->', '=>', 'Hello->']
sys.ps1 = random.choice(random_prompts)

To execute this when your python interpreter starts, you can follow this guide: https://docs.python.org/2/tutorial/appendix.html#the-interactive-startup-file

Answer 4

Nice question. The >>> prompt is in sys.ps1, the ... in sys.ps2. The next question would be how to change this randomly. Just as a demonstration of changing it by hand:

>>> import sys
>>> sys.ps1 = '<<<'
<<<sys.ps1 = '<<< '
<<< sys.ps2 = '.?. '
<<< for i in line:
.?.