python替换文件中的某几行操作技巧

　　try:

　　with open(file_path, "r") as file:

　　file_content = file.read()

　　except Exception as e:

　　return str(e)

　　# 设置改写内容

　　updated_content = ""

　　# 查找修改

　　start_index_1 = file_content.find("start_sentence_1")#要确保查找元素的唯一性

　　end_index_1 = file_content.find("end_sentence_1",start_index_1,)

　　start_index_2 = file_content.find("start_sentence_2",end_index_1)

　　end_index_2 = file_content.find("end_sentence_2",start_index_2,)

　　start_index_3 = file_content.find("start_sentence_3",end_index_2)

　　end_index_3 = file_content.find("end_sentence_3",start_index_3,)

　　start_index_4 = file_content.find("start_sentence_4",end_index_3)

　　end_index_4 = file_content.find("end_sentence_4",start_index_4,)

　　if (

　　start_index_1 == -1

　　or end_index_1 == -1

　　or start_index_2 == -1

　　or end_index_2 == -1

　　or start_index_3 == -1

　　or end_index_3 == -1

　　or start_index_4 == -1

　　or end_index_4 == -1

　　):

　　print("未找到待修改位置")

　　return -1

　　#

　　updated_content = file_content[:start_index_1]#获取这行代码之前的内容

　　updated_content += "start_sentence_1和end_sentence_1之间的内容"

　　updated_content +=file_content[end_index_1:start_index_2]

　　updated_content += "start_sentence_2和end_sentence_2之间的内容"

　　updated_content +=file_content[end_index_2:start_index_3]

　　updated_content += "start_sentence_3和end_sentence_3之间的内容"

　　updated_content +=file_content[end_index_3:start_index_4]

　　updated_content += "start_sentence_4和end_sentence_4之间的内容"

　　updated_content += file_content[end_index_4:]

　　##此时updated_content就是修改后的完整文件内容

　　if updated_content != "":

　　with open(file_path, "w") as file:

　　file.write(updated_content)

　　else:

　　print("修改失败")

　　return -1