python - 搜索字符串并替换值

Question

这是我的代码，

import os, os.path
import collections
import sys
import re

DIR_DAT = "dat"
DIR_OUTPUT = "output"
filenames = []
data = []

#in case if output folder doesn't exist
if not os.path.exists(DIR_OUTPUT):
    os.makedirs(DIR_OUTPUT)

input_file = 'axcfgpasww-from-server.dat'
element = sys.argv[1]
output_value = sys.argv[2]

with open(input_file) as infile, open('axcfgpasww-modified.dat', "w") as outfile:
    if element in open(input_file).read():
        regex = re.findall("\s*([\S\s]+)", element)

        outfile.write(regex[0])
        print(regex[0])
    else:
        print('No match found')

输入文件:

CMD_VERS=2
CMD_TRNS=O
CMD_REINIT=N
CMD_ORDER=MAJECR
CMD_COMM=2590552
NUM_COMM:nNN0.7=2590552

我这样执行我的脚本:modify_file.py NUM_COMM:nNN0.7 Hello world !

因此，如果文件中存在NUM_COMM:nNN0.7，则会在新的 axcfgpasww-modified.dat 文件中写入“NUM_COMM:nNN0.7”。

但是我想做的是执行上面写的命令。结果是输入文件，只有新值。

所以我的输出文件是:

CMD_VERS=2
CMD_TRNS=O
CMD_REINIT=N
CMD_ORDER=MAJECR
CMD_COMM=2590552
NUM_COMM:nNN0.7=Hello world !

有人可以帮我解决这个问题吗？

谢谢!

Answer 1

我对您的原始代码进行了一些重构，并使其产生您寻求的输出，

import os, os.path
import collections
import sys
import re

DIR_DAT = "dat"
DIR_OUTPUT = "output"
filenames = []
data = []
found = False

#in case if output folder doesn't exist
if not os.path.exists(DIR_OUTPUT):
    os.makedirs(DIR_OUTPUT)

input_file = 'axcfgpasww-from-server.dat'
element = sys.argv[1]
output_value = sys.argv[2]

with open(input_file) as infile:
    for line in infile.readlines():
        if element in line:
            old_value = line.split("=")[1]
            data.append(line.replace(old_value, output_value))
            found = True
        else:
            data.append(line)
if not found:
    print('No match found')

with open(input_file, 'w') as outfile:
    for line in data:
        outfile.write(line)

输出:

CMD_VERS=2
CMD_TRNS=O
CMD_REINIT=N
CMD_ORDER=MAJECR
CMD_COMM=2590552
NUM_COMM:nNN0.7=Hello World!

希望这有帮助