猜数字游戏：我如何接受数字前面输入“ guess =”的猜测？

Question

import random
guess = input("What is your guess?")
answer = random.randint(0,100)

while guess != answer:
    try:
        guess = float(guess)
        if guess > answer:
            print ("Your guess is too high!")
        elif guess < answer:
            print ("Your guess is too low!")
        elif guess == answer:
            print ("Congratulations!")
            break
        guess = input("What is your guess?")
        continue
    except ValueError:
        print ("Bad input. Try again!")
        guess = input("What is your guess?")

So my code works except that when i enter for example: guess = 30, it seems the input as invalid...how can I make it so it accepts it as a correct guess?

New to python here :) Thanks.

Answer 1

I copied and pasted your code into Python 3.5, and....apart from needing to indent everything after the while statement it worked fine.

Are you inputting just the number: 30

...or "guess = 30"? Because that does cause a problem since it's not a number. You only need to input the number. :)

If you want to accept "guess = 30" then:

import random
import re ###<-Add this

guess = input("What is your guess?")
answer = random.randint(0,100)

while guess != answer:
    try:
        guess = re.sub("[^0-9]", "", guess) ###<- Add this
        guess = float(guess)
        if guess > answer:
            print ("Your guess is too high!")
        elif guess < answer:
            print ("Your guess is too low!")
        elif guess == answer:
            print ("Congratulations!")
            break
        guess = input("What is your guess?")
        continue
    except ValueError:
        print ("Bad input. Try again!")
        guess = input("What is your guess?")

These two lines will use Regular Expressions to strip the input of any non numeric characters before processing.

Answer 2

It depends on how much you have learnt in that class, but adding the following line should allow you to accept both 30 and guess = 30 (or even foo=bar=30 ):

...
while guess != answer:
    guess = guess.split('=')[-1]    # Add this line
    try:
        guess = float(guess)
        ...

It simply splits the input using = as a delimiter and only uses the last part ( [-1] ).

Answer 3

So I reordered your code:

• I narrowed try/except down to just the line which can cause the ValueError, because that makes it clear what particular error this except block is trying to handle - puts the error handling near the source of the error. This also makes a good reason to have continue because it now skips the "too high/too low" code, instead of in your code it does nothing.

• I changed the while loop condition so it says while True: to make it an infinite loop. In your code, while guess != answer implies that it will break when the guess is correct, you actually use break to exit the loop, so that is misleading. It would be sensible to use while guess != answer and not have break anywhere, but if you have to use break as part of the assignment then my code has some 'reason' to use it (breaking an infinite loop).

• I moved the guess = input(...) code inside the loop only, because it doesn't need to be duplicated at the top or inside the error handling. (Imagine if you had to change the text, 3 places is more annoying than 1 place).

• There are lots of ways to handle the guess = 30 input. You could literally handle that, and only that, by looking for if "guess = " in guess: and then if that text matches, use guess = guess.replace("guess = ", "") to replace it away, leaving just the number. Or use regular expressions, as another answer has used to drop text and leave digits, or use string split() , as yet another answer has. My answer here has filter() which filters something using a test - in this case it tests if something is a number, and only allows numbers through, so it drops all the text. Same as the regex is doing, really, just a different approach.

code:

import random

answer = random.randint(0,100)

while True:
    guess = input("What is your guess?")

    # filters out only the numbers
    # and makes them into a string, e.g.
    # 1) "guess = 30"
    # 2) [3,0]
    # 3) "30"
    guess = ''.join(filter(str.isdigit, guess))

    try:
        guess = float(guess)
    except ValueError:
        print ("Bad input. Try again!")
        continue

    if guess > answer:
        print ("Your guess is too high!")
    elif guess < answer:
        print ("Your guess is too low!")
    else:
        print ("Congratulations!")
        break

Try it online at repl.it