Python：搜索键，并在很大的Windows文件中用恒定值替换“，”之前的下一个单词

Question

我最近才开始学习Python，并提出了需要您帮助的要求。 我有大型机背景，这是一个非常简单的要求，可以使用DFSORT来完成，但是在python中，我搜索了论坛和Google，但找不到此问题的任何线索。

我有一个很大的Windows文件，它可以是3GB到5GB甚至更大。 我的要求是在每行中用一个关键字搜索该文件，如果找到该关键字，则用XXXXXXXXXX替换（结束）“，”之前的下一个单词，关键字始终为“ name：”，要替换的值始终位于（ ，）之后的键。 可能并非所有的行都有键。 如果要替换的值为NULL，则必须从替换中忽略该值

样本输入文件：-

this is the name: roger,who won australian open
yes name: rafael nadal,who won french open
name: novak, is injured for this season
propably greatest of all time name: roger, had won wimbledon again.
this is the name: NULL,who will win US open !!!

输出文件

this is the name: XXXXXXXXXX,who won australian open
yes name: XXXXXXXXXX,who won french open
name: XXXXXXXXXX, is injured for this season
propably greatest of all time name: XXXXXXXXXX, had won wimbledon again.
this is the name: NULL,who will win US open !!!

Answer 1

您可以使用正则表达式捕获name: anysequenceofcharacters,字符串，并将其替换为name: XXXXXXXXXX, name: anysequenceofcharacters,

import re
with open('in', "rt") as fin:
with open('out', "wt") as fout:
    for line in fin:
        fout.write(re.sub('name:(?! NULL)([^,]+),', 'name: XXXXXXXXXX,', line))

Answer 2

无法发表评论，因此这是在@aoiee的基础上建立的答案，该答案将遍历文件：

with open('filename.txt', 'r') as f:
    lines = file.read()
    text = re.sub('name:(?! NULL)([^,]+),', 'name: XXXXXXXXXX,', lines)

with open('out.txt', 'w') as out:
    out.write(text)

Answer 3

除了aoiee的答案，您还可以阅读并重写文字，

如果数据很多，可能需要更长的时间

import fileinput
import re
with open('path to file.txt or whatever', 'r') as file :
  filedata = file.read()
new_data = re.sub('name:([^,]+),', 'name: XXXXXXXXXX,', filedata)
with open('path to file.txt or whatever', 'w') as file:
  file.write(new_data)

Answer 4

如果每一行都在换行符上，则可以执行以下操作而无需for循环：

def repel(mo):
    if mo.group(3) == 'NULL':
        return '{}{}{}{}'.format(mo.group(1), mo.group(2), mo.group(3), mo.group(4))
    return '{}{}{}{}'.format(mo.group(1), mo.group(2), 'XXXX,', mo.group(4))

pattern = re.compile('(.*)(name: )(\w+,)?(.*)')
re.sub(pattern, repel, _in, re.DOTALL)

基本上在每次比赛时都调用排斥功能，该功能将name:后的部分替换为XXXX 。