In python I have a function which has an input statement, and assume that the function is a blackbox so I cannot edit the function. Instead of letting users to type and input, I want to feed a string to the input statement.
I have found a way to do so by starting a subprocess to run the function and feed the string as stdin.
Another approach is just using PIPE.
Is there any purely python way to achieve it?
You can patch the module's function e.g. mymodule.input = myfunc, then your function will be called and afterwards just return a string from your function.
# mymodule
def func():
print(input())
# main
import mymodule
def custom():
return "my custom input"
mymodule.input = custom
mymodule.func()
however this might need to happen before mymodule is imported anywhere else. Depending on how the input() is called (e.g. as a global call in a module thus (import module already calling it indirectly) vs in a function, when it'd look into the globals() which would be patched)
Now, there's an alternative with deeper patching, but we can't do much as input() is a built-in and implemented in C (so not much of a patching available :( ). We can, however, utilize a custom sys.stdin such as io.StringIO() by which you can write to own "stdin" (it's not the real process' STDIN, just a buffer replacement, but that doesn't matter for this use-case).
Then a simple sys.stdin.write() with rewinding will do (again, has to happen before input() is called:
import sys
from io import StringIO
sys.stdin = StringIO()
sys.stdin.write("myinput")
sys.stdin.seek(0) # rewind, so input() can read
text = input()
print(f"{text=}")
Between processes, as you've mentioned, use PIPE from subprocess or similar module.
sys.stdin included.import mymodule
class Person:
def __init__(self, name):
self.name = name
@property
def email(self):
return f"{name}@gmail.com}"
P = Person("Praddyumn")
mymodule.email = p.email
Here mymodule is an example of a module that takes email as an argument, but in class Person we have email as a function, but by using the @property decorator this function email becomes an atribute, so you can use this with pure Python.
inputbefore calling it, you can use this: stackoverflow.com/a/63522511/8612463