从我制作的另一个脚本中以python导入函数

Question

I'm kind of stuck at a problem where my teacher wants me to import functions from another script

def readint():
    prompt = int(input("Enter an integer: "))
    print(" You entered: ",prompt," and the type is", type(prompt))

and then on the other program I can get it to import like

import test 

test.readint()

but when I try to get it exactly how she wants

test.readint(prompt)

I can't seem to get it to work. I tried this but it doesn't seem to work

def readint(prompt):
prompt = int(input("Enter an integer: "))
print(" You entered: ",prompt," and the type is", type(prompt))
return prompt

any explanation would be greatly appreciated!

Answer 1

You may be having problems with the commas in the print statement.

When I ran your initial program, I got this:

>>> 
Enter an integer: 3
(' You entered: ', 3, ' and the type is', <type 'int'>)

Which doesn't seem to be like what you wanted (it's a tuple)

What you seem to want to print is the string,

You entered: 3 and the type is <type 'int'>

To do this, you need to cast your variables to strings.

---

test.py

def readint(prompt):
    prompt = int(input("Enter an integer: "))
    print ("You entered: " + str(prompt) + " and the type is " + str(type(prompt)))
    return prompt

main.py

import temp

prompt = None
temp.readint(prompt)

Note the + operators and str casts

---

For me, this outputs the following:

>>> 
Enter an integer: 3
You entered: 3 and the type is <type 'int'>

Which looks to be what you are looking for.

---

As a side note, I'm not sure why you want to pass in the prompt variable because it can be left out and there is no reason to have it in there. Simply removing it from the function definition and not passing it in is perfectly valid:

def readint():
    ...

and

import test
test.readint()

---

Happy Coding!

--Elipzer

Answer 2

First off, instead of printing the result to the screen when you get the value of the prompt, try returning it as a string. That way, you can assign the return value to a variable and access it later. Pretty neat, huh? Your second attempt already had it, but there were two little problems:

There's no point in passing an argument to this function. This is because input() already stores a value in a variable, so there'd be no point in passing an argument, you could just create a function variable and store it in there. Also, there'd be no point in doing " and the type is",type(prompt)) . The reason for this is because we already know it's an integer: you converted the result of prompt to an integer after you got it's string value. If you passed a value to prompt that couldn't be converted to integer, you'd get a ValueError . So, try using this code:

def readint():
    prompt = int(input("Enter an integer: "))
    return "You entered " + str(prompt)

That way, in your other file you can do this:

>>> import test
>>> a = test.readint()
Enter an integer7
>>> a
'You entered 7'
>>> 

(Keep in mind that the three > symbols aren't python code, it comes from the shell) If you were to enter a invalid value to be converted to an integer, it'd raise a ValueError . How can we prevent this? You can use a try , except statement. Basically, what this does, is it tries to do something, then, if an exception is raised during that process, it does something else.

So, all in all. Your code would look like this:

def readint():
    try:
        prompt = int(input("Enter an integer: "))
    except ValueError:
        return "Invalid value! It must be a number."
    return "You entered " + str(prompt)