Python ValueError: chr() arg not in range(256)

问题

So I am learning python and redoing some old projects. This project involves taking in a dictionary and a message to be translated from the command line, and translating the message. (For example: "btw, hello how r u" would be translated to "by the way, hello how are you".

We are using a scanner supplied by the professor to read in tokens and strings. If necessary I can post it here too. Heres my error:

Nathans-Air-4:py1 Nathan$ python translate.py test.xlt test.msg
Traceback (most recent call last):
  File "translate.py", line 26, in <module>
    main()
  File "translate.py", line 13, in main
    dictionary,count = makeDictionary(commandDict)
  File "/Users/Nathan/cs150/extra/py1/support.py", line 12, in makeDictionary
    string = s.readstring()
  File "/Users/Nathan/cs150/extra/py1/scanner.py", line 105, in readstring
    return self._getString()
  File "/Users/Nathan/cs150/extra/py1/scanner.py", line 251, in _getString
    if (delimiter == chr(0x2018)):
ValueError: chr() arg not in range(256)

Heres my main translate.py file:

from support import *
from scanner import *
import sys

def main():
    arguments = len(sys.argv)
    if arguments != 3:
        print'Need two arguments!\n'
        exit(1)
    commandDict = sys.argv[1]
    commandMessage = sys.argv[2]

    dictionary,count = makeDictionary(commandDict)

    message,messageCount = makeMessage(commandMessage)

    print(dictionary)
    print(message)

    i = 0
    while count < messageCount:
        translation = translate(message[i],dictionary,messageCount)
        print(translation)
        count = count + 1
        i = i +1
    main()

And here is my support.py file I am using...

from scanner import *

def makeDictionary(filename):
    fp = open(filename,"r")

    s = Scanner(filename)
    lyst = []
    token = s.readtoken()
    count = 0
    while (token != ""):
        lyst.append(token)
        string = s.readstring()
        count = count+1
        lyst.append(string)
        token = s.readtoken()
    return lyst,count

def translate(word,dictionary,count):
    i = 0
    while i != count:
        if word == dictionary[i]:
            return dictionary[i+1]
            i = i+1
        else:
            return word
            i = i+1
    return 0

def makeMessage(filename):
    fp = open(filename,"r")

    s = Scanner(filename)
    lyst2 = []
    string = s.readtoken()
    count = 0
    while (string != ""):
        lyst2.append(string)
        string = s.readtoken()
        count = count +  1
    return lyst2,count

Does anyone know whats going on here? I've looked through several times and i dont know why readString is throwing this error... Its probably something stupid i missed

回答1:

chr(0x2018) will work if you use Python 3.

You have code that's written for Python 3 but you run it with Python 2. In Python 2 chr will give you a one character string in the ASCII range. This is an 8-bit string, so the maximum parameter value for chris 255. In Python 3 you'll get a unicode character and unicode code points can go up to much higher values.

回答2:

The issue is that the character you're converting using chr isn't within the range accepted (range(256)). The value 0x2018 in decimal is 8216.

Check out unichr, and also see chr.

来源：https://stackoverflow.com/questions/27327901/python-valueerror-chr-arg-not-in-range256

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python

dictionary

translate