如何使这个Python脚本与Python3一起工作？

我下载了这个脚本来帮助我转换一些PNG。然而，从2003年开始，在我第一次尝试运行它时，它给了我异常语法错误。我设法解决了这个问题，并再次运行了它。然后它给了我打印语法的错误。我也把它们修好了。现在我完全不知道发生了什么，除了剧本不起作用

剧本是：

from struct import *
from zlib import *
import stat
import sys
import os

def getNormalizedPNG(filename):
    pngheader = "\x89PNG\r\n\x1a\n"

    file = open(filename, "rb")
    oldPNG = file.read()
    file.close()

    if oldPNG[:8] != pngheader:
        return None

    newPNG = oldPNG[:8]

    chunkPos = len(newPNG)

    # For each chunk in the PNG file    
    while chunkPos < len(oldPNG):

        # Reading chunk
        chunkLength = oldPNG[chunkPos:chunkPos+4]
        chunkLength = unpack(">L", chunkLength)[0]
        chunkType = oldPNG[chunkPos+4 : chunkPos+8]
        chunkData = oldPNG[chunkPos+8:chunkPos+8+chunkLength]
        chunkCRC = oldPNG[chunkPos+chunkLength+8:chunkPos+chunkLength+12]
        chunkCRC = unpack(">L", chunkCRC)[0]
        chunkPos += chunkLength + 12

        # Parsing the header chunk
        if chunkType == "IHDR":
            width = unpack(">L", chunkData[0:4])[0]
            height = unpack(">L", chunkData[4:8])[0]

        # Parsing the image chunk
        if chunkType == "IDAT":
            try:
                # Uncompressing the image chunk
                bufSize = width * height * 4 + height
                chunkData = decompress( chunkData, -8, bufSize)

            except Exception as e:
                # The PNG image is normalized
                return None

            # Swapping red & blue bytes for each pixel
            newdata = ""
            for y in xrange(height):
                i = len(newdata)
                newdata += chunkData[i]
                for x in xrange(width):
                    i = len(newdata)
                newdata += chunkData[i+2]
                    newdata += chunkData[i+1]
                    newdata += chunkData[i+0]
                    newdata += chunkData[i+3]

            # Compressing the image chunk
            chunkData = newdata
            chunkData = compress( chunkData )
            chunkLength = len( chunkData )
            chunkCRC = crc32(chunkType)
            chunkCRC = crc32(chunkData, chunkCRC)
            chunkCRC = (chunkCRC + 0x100000000) % 0x100000000

        # Removing CgBI chunk        
        if chunkType != "CgBI":
            newPNG += pack(">L", chunkLength)
            newPNG += chunkType
            if chunkLength > 0:
                newPNG += chunkData
            newPNG += pack(">L", chunkCRC)

        # Stopping the PNG file parsing
        if chunkType == "IEND":
            break

    return newPNG

def updatePNG(filename):
    data = getNormalizedPNG(filename)
    if data != None:
        file = open(filename, "wb")
        file.write(data)
        file.close()
        return True
    return data

def getFiles(base):
    global _dirs
    global _pngs
    if base == ".":
        _dirs = []
        _pngs = []

    if base in _dirs:
        return

    files = os.listdir(base)
    for file in files:
        filepath = os.path.join(base, file)
        try:
            st = os.lstat(filepath)
        except os.error:
            continue

        if stat.S_ISDIR(st.st_mode):
            if not filepath in _dirs:
                getFiles(filepath)
                _dirs.append( filepath )

        elif file[-4:].lower() == ".png":
            if not filepath in _pngs:
                _pngs.append( filepath )

    if base == ".":
        return _dirs, _pngs

print ("iPhone PNG Images Normalizer v1.0")
print (" ")
print ("[+] Searching PNG files..."),
dirs, pngs = getFiles(".")
print ("ok")

if len(pngs) == 0:
    print (" ")
    print ("[!] Alert: There are no PNG files found. Move this python file to the folder that contains the PNG files to normalize.")
    exit()

print (" ")
print (" -  %d PNG files were found at this folder (and subfolders).") % len(pngs)
print (" ")
while True:
    normalize = raw_input("[?] Do you want to normalize all images (Y/N)? ").lower()
    if len(normalize) > 0 and (normalize[0] == "y" or normalize[0] == "n"):
        break

normalized = 0
if normalize[0] == "y":
    for ipng in xrange(len(pngs)):
        perc = (float(ipng) / len(pngs)) * 100.0
        print ("%.2f%% %s") % (perc, pngs[ipng])
        if updatePNG(pngs[ipng]):
            normalized += 1
print (" ")
print ("[+] %d PNG files were normalized.") % normalized

现在，当我在DOS窗口中运行它时，出现以下错误：

C:\wamp\www\py>ipin.py
iPhone PNG Images Normalizer v1.0

[+] Searching PNG files...
ok

 -  %d PNG files were found at this folder (and subfolders).
Traceback (most recent call last):
  File "C:\wamp\www\py\ipin.py", line 158, in <module>
    print (" -  %d PNG files were found at this folder (and subfolders).") % len(pngs)
TypeError: unsupported operand type(s) for %: 'NoneType' and 'int'

---

我该怎么办？

您可能希望将%运算符移到括号内

print (" -  %d PNG files were found at this folder (and subfolders)." % len(pngs))

---

当您尝试%strlenpngs时会发生什么情况？

在Python 2中，纯字符串文本是ByTestRing，而在Python 3中，它们是Unicode字符串。如果要编写bytestring文本，请使用b前缀，例如b\x89PNG\r\n\x1a\n。Python3在混合使用bytestring和Unicode字符串时非常严格

其他不同之处在于，在Python 3中，print现在是一个普通函数，而不是一个语句，range函数返回一个生成器，就像Python 2中的xrange一样，而该输入就像Python 2中的raw_输入。在Python 3中，没有与Python 2的输入函数等价的函数-它被删除是因为它被认为是不安全的

顺便说一句，我试图将代码翻译成Python 3，但不鼓励使用from something import*，因为它可能会无意中隐藏许多名称；仅导入您希望使用的名称：

from struct import *
from zlib import *
import stat
import sys
import os

def getNormalizedPNG(filename):
    pngheader = b"\x89PNG\r\n\x1a\n"

    file = open(filename, "rb")
    oldPNG = file.read()
    file.close()

    if oldPNG[:8] != pngheader:
        return None

    newPNG = oldPNG[:8]

    chunkPos = len(newPNG)

    # For each chunk in the PNG file    
    while chunkPos < len(oldPNG):

        # Reading chunk
        chunkLength = oldPNG[chunkPos:chunkPos+4]
        chunkLength = unpack(">L", chunkLength)[0]
        chunkType = oldPNG[chunkPos+4 : chunkPos+8]
        chunkData = oldPNG[chunkPos+8:chunkPos+8+chunkLength]
        chunkCRC = oldPNG[chunkPos+chunkLength+8:chunkPos+chunkLength+12]
        chunkCRC = unpack(">L", chunkCRC)[0]
        chunkPos += chunkLength + 12

        # Parsing the header chunk
        if chunkType == b"IHDR":
            width = unpack(">L", chunkData[0:4])[0]
            height = unpack(">L", chunkData[4:8])[0]

        # Parsing the image chunk
        if chunkType == b"IDAT":
            try:
                # Uncompressing the image chunk
                bufSize = width * height * 4 + height
                chunkData = decompress( chunkData, -8, bufSize)

            except Exception as e:
                # The PNG image is normalized
                return None

            # Swapping red & blue bytes for each pixel
            newdata = b""
            for y in range(height):
                i = len(newdata)
                newdata += chunkData[i]
                for x in range(width):
                    i = len(newdata)
                    newdata += chunkData[i+2]
                    newdata += chunkData[i+1]
                    newdata += chunkData[i+0]
                    newdata += chunkData[i+3]

            # Compressing the image chunk
            chunkData = newdata
            chunkData = compress( chunkData )
            chunkLength = len( chunkData )
            chunkCRC = crc32(chunkType)
            chunkCRC = crc32(chunkData, chunkCRC)
            chunkCRC = (chunkCRC + 0x100000000) % 0x100000000

        # Removing CgBI chunk        
        if chunkType != b"CgBI":
            newPNG += pack(">L", chunkLength)
            newPNG += chunkType
            if chunkLength > 0:
                newPNG += chunkData
            newPNG += pack(">L", chunkCRC)

        # Stopping the PNG file parsing
        if chunkType == b"IEND":
            break

    return newPNG

def updatePNG(filename):
    data = getNormalizedPNG(filename)
    if data != None:
        file = open(filename, "wb")
        file.write(data)
        file.close()
        return True
    return data

def getFiles(base):
    global _dirs
    global _pngs
    if base == ".":
        _dirs = []
        _pngs = []

    if base in _dirs:
        return

    files = os.listdir(base)
    for file in files:
        filepath = os.path.join(base, file)
        try:
            st = os.lstat(filepath)
        except os.error:
            continue

        if stat.S_ISDIR(st.st_mode):
            if not filepath in _dirs:
                getFiles(filepath)
                _dirs.append( filepath )

        elif file[-4:].lower() == ".png":
            if not filepath in _pngs:
                _pngs.append( filepath )

    if base == ".":
        return _dirs, _pngs

print ("iPhone PNG Images Normalizer v1.0")
print (" ")
print ("[+] Searching PNG files..."),
dirs, pngs = getFiles(".")
print ("ok")

if len(pngs) == 0:
    print (" ")
    print ("[!] Alert: There are no PNG files found. Move this python file to the folder that contains the PNG files to normalize.")
    exit()

print (" ")
print (" -  %d PNG files were found at this folder (and subfolders)." % len(pngs))
print (" ")
while True:
    normalize = input("[?] Do you want to normalize all images (Y/N)? ").lower()
    if len(normalize) > 0 and (normalize[0] == "y" or normalize[0] == "n"):
        break

normalized = 0
if normalize[0] == "y":
    for ipng in range(len(pngs)):
        perc = (float(ipng) / len(pngs)) * 100.0
        print ("%.2f%% %s" % (perc, pngs[ipng]))
        if updatePNG(pngs[ipng]):
            normalized += 1
print (" ")
print ("[+] %d PNG files were normalized." % normalized)

---

你试过用它跑步吗？你也可以安装python的2.7版，这是大多数人都在使用的版本。有没有可能得到一些记录在案的统计数据，说明有多少人使用每个版本的python？@noctiskytower据我所知，没有，我只是从轶事中说出来的，因为我从来没有见过使用python 3的人，这里似乎很少有问题使用Python 3。现在我得到了以下错误：$ipin.py./ipin.py:line 25:from:command not found./ipin.py:line 26:from:command not found./ipin.py:line 27:import:command not found./ipin.py:line 28:import:command not found./ipin.py:line 29:import:command not found./ipin.py:line 31:syntax意外标记附近出错。/ipin.py:line 31:`def getNormalizedPNGfilename:抱歉，我确实不太使用标记：/反正，使用2to3，我得到了这个错误：/bin/env:python:没有这样的文件或目录我得到了：$ipin_py.py./ipin_py.py:line 1:from:command not found./ipin_py.py:line 2:from:command not found./ipin_py.py:line 3:import:command not found./ipin_py.py:line 4:import:command not found./ipin_py.py:line 5:import:command not found./ipin_py.py:line 7:意外标记“.”/ipin_py.py:第7行：def getNormalizedPNGfilename:“那是什么$？你还在Windows上运行它吗？我之所以这么问，是因为在我看来，它似乎没有将其识别为Python脚本。如果您在没有shebang行的Linux上运行它，可能会发生这种情况/关于shebang的usr/bin/python细节可能会有所不同。这不是一个答案，显然也不打算作为一个答案；请把它拿走。