python3找到最后出現的字符串然后寫

Question

我正在嘗試創建一個腳本，如果域不存在（最后出現###標記並寫入下一行），該腳本會將一個區域添加到named.conf的末尾。 我似乎陷入了列表與文件對象的悖論。 如果我以列表形式打開，則可以找到我的字符串，但是如果不先關閉列表對象就無法寫入文件，這不是一個好的解決方案。 如果我將文件作為文件對象打開，則在嘗試使用find時出現對象錯誤

Traceback (most recent call last):
  File "named.py", line 10, in <module>
    answer = mylist.find('#--#')
AttributeError: 'list' object has no attribute 'find'

要么

  File "named.py", line 12, in <module>
    f.write("   zone \""+name+"\" {\n")
io.UnsupportedOperation: not writable

在Python3中打開文件進行搜索和編輯的正確方法是什么？

import sys
import string
import os.path

name = input("Enter the domain to configure zone for? ")
#fd = open( "named.conf", 'w')
if os.path.lexists("named.conf"):
        with open('named.conf') as f:
                mylist = list(f)
                print(mylist)
                f.write("      zone \""+name+"\" {\n")

Answer 1

該文件僅開放供讀取，因此這就是您收到錯誤的原因，無論您使用in還是==取決於該行可以包含域名還是該行必須等於域名。

if os.path.lexists("named.conf"):  
    with open('named.conf') as f:
        found = False
        for line in f:
            # if domain is in the line break and end
            if name in line.rstrip():
                found = True
                break
    # if found is still False we did not find the domain
    # so open the file and append the domain name
    if not found:
        with open('named.conf', "a") as f:
            f.write("      zone \{}\ {\n".format(name))

要查找最后出現的一行並在以下位置寫一行：

if os.path.lexists("named.conf"):
        with open('named.conf') as f:
            position = -1
            for ind, line in enumerate(f):
                # if line is  #--#
                if "#--#" == line.rstrip():
                    # keep updating index so will point to last occurrence at the end
                    position = ind 
        if position != -1: # if we found at least one match
            with open('named.conf', "r+") as f:
                for ind, line in enumerate(f):
                    if ind == position: # find same line again
                        # write line and new line
                        f.write("{}{}\n".format(line,your_new_line))
                    else:
                        f.write(line)