Python正则表达式匹配多行文本块但不替换

Question

好的，我有一段代码：

def findNReplaceRegExp(file_name, regexp, replaceString, verbose=True, confirmationNeeded=True):
'''Replaces the oldString with the replaceString in the file given,\
   returns the number of replaces
'''
    # initialize local variables
    cregexp = re.compile(regexp, re.MULTILINE | re.DOTALL)
    somethingReplaced = True
    ocurrences = 0
    isAborted = False

    # open file for read
    file_in = open(file_name, 'r')
    file_in_string = file_in.read()
    file_in.close()

    while somethingReplaced:
        somethingReplaced = False
        # if the regexp is found
        if cregexp.search(file_in_string):
            # make the substitution
            replaced_text = re.sub(regexp, replaceString, file_in_string)
            if verbose == True:
                # calculate the segment of text in which the resolution will be done

                # print the old string and the new string
                print '- ' + file_in_string
                print '+ ' + replaced_text
                if confirmationNeeded:
                    # ask user if this should be done
                    question = raw_input('Accept changes? [Yes (Y), No (n), Abort (a)] ')
                    question = string.lower(question)
                    if question == 'a':
                        isAborted = True
                        print "Aborted"
                        break
                    elif question == 'n':
                        pass
                    else:
                        file_in_string = replaced_text
                        somethingReplaced = True
                        ocurrences = ocurrences + 1
            else:
                file_in_string = replaced_text
                somethingReplaced = True
                ocurrences = ocurrences + 1

    # if some text was replaced, overwrite the original file
    if ocurrences > 0 and not isAborted:
        # open the file for overwritting
        file_out = open(file_name, 'w')
        file_out.write(file_in_string)
        file_out.close()
        if verbose: print "File " + file_name + " written"

还有这个文件：

CMC_SRS T10-24400: DKU Data Supply: SN Time Break-In Area
CMC_SRS T10-24401: DKU Data Supply: SN Transponder Enable Area
CMC_SRS T10-24402: DKU Data Supply: SN Adjust Master Slave Area
CMC_SRS T10-24403: DKU Data Supply: SN ATEC Area
CMC_SRS T10-24404: DKU Data Supply: SN PTEC Area
CMC_SRS T10-25449: DKU Data Supply: SN Self Init Area
CMC_SRS T10-24545: DKU Data Supply: SN Time Area
CMC_SRS T10-4017: RFI display update
CMC_SRS T10-6711: Radio Interface to PLS Equipment
CMC_SRS T10-21077: Safety Requirements: Limit FM Power

当我用这个文件和这些参数来调用这个过程时：

regexp=24403.*24404
replace=TESTSTRING

我得到了一个匹配（它找到了相符的内容并询问该怎么做），但是在替换的时候却什么都没发生……这是怎么回事呢？

Answer 1

你在使用 cregexp，这个工具是设置了多行选项的，但接下来你却用 regexp 来替换，这个工具可能有多行选项，也可能没有。