python TypeError: argument 1 must be string or read-only character buffer, not None

Question

这是我的代码： def main():

    if len(sys.argv) != 3:

        fname = "OP.tex"
        dot_ind = fname.index(".") + 1
        ofname = fname[:dot_ind] + "1." + fname[dot_ind:]

    else:

        fname = sys.argv[1]
        ofname = sys.argv[2]
    print (fname, "+",ofname)
    writeout(ofname, replacement(readin(fname)))
def replacement(content):
   pattern = re.compile(r'(?<=\\\[-16pt]\n)([\s\S]*?)(?=\\\n\thinhline)')
   re.findall(pattern, content)

if __name__ == "__main__":
    main()

为此我收到以下错误：

File "test.py", line 30, in main
writeout(ofname, replacement(readin(fname)))
File "/home/utilities.py", line 138, in writeout
out.write(content)
TypeError: argument 1 must be string or read-only character buffer, not None

writeout 是另一个文件中的一个函数，它告诉 python 在哪里输出内容，如下所示：

def writeout(filename, content, append=False):
    """
    Writes content to file filename.
    """

    mode = "w"

    #append to the file instead of overwriting
    if append:
        mode = "a"

    #write content
    with open(filename, mode) as out:
        out.write(content)

fname 和 ofname（输入和输出文件名）是正确的，为什么当它是一个字符串时程序说参数为 None？

非常感谢。

Answer 1

您的 replacement 函数必须 return 一个字符串，目前它 return 是 None。所以，改变语句

re.findall(pattern, content)

类似于

return ' '.join(re.findall(pattern, content))

请注意，您不能只 return re.findall 的结果，因为那是一个列表，而不是字符串；您必须以某种方式从该结果中列出一份清单。

python TypeError: argument 1 must be string or read-only character buffer, not None

python TypeError: argument 1 must be string or read-only character buffer, not None

python

regex

typeerror

python-2.7