Python 3 - TypeError: a bytes-like object is required, not 'str'

问题

I'm working on a lesson from Udacity and am having some issue trying to find out if the result from this site returns true or false. I get the TypeError with the code below.

   from urllib.request import urlopen
    #check text for curse words  
    def check_profanity():
        f = urlopen("http://www.wdylike.appspot.com/?q=shit")
        output = f.read()
        f.close()
        print(output)
        if "b'true'" in output:
            print("There is a profane word in the document")

    check_profanity()

The output prints b'true' and I'm not really sure where that 'b' is coming from.

回答1:

In python 3 strings are by default unicode. The b in b'true' means that the string is a byte string and not unicode. If you don't want that you can do:

 from urllib.request import urlopen
 #check text for curse words  
 def check_profanity():
    with urlopen("http://www.wdylike.appspot.com/?q=shit") as f:
        output = f.read().decode('utf-8')
        if output:
            if "true" in output:
                print("There is a profane word in the document")

check_profanity()

Using with will close the urlopen connection automatically.

来源：https://stackoverflow.com/questions/40211408/python-3-typeerror-a-bytes-like-object-is-required-not-str