python - 字符串操作/正则表达式 - 查找和替换

Question

我正在尝试替换下面 txt 文件中 . 之后的每个单词:

line1
line2
field: [orders.cancelled,orders.delivered,orders.reached
orders.pickup,orders.time]
some line
some line

我有一本字典:

   d = {'cancelled':'cancelled_at', 'deliver':'xxx'}

我正在运行以下代码。但是，我得到的是部分匹配的结果，即

我看到新文件有下面的话

field: [orders.cancelled_at, orders.xxxed ..........

这里从单词 delivered 开始，程序仍然替换前 7 个单词 (deliver) 并在最后添加 'ed'。我不知道为什么

with open('list.txt', 'r') as g:
    text = g.read()
    for k in d:
        before = f'.{k}'
        after = f'.{d[k]}
        #print(before)
        #print(after)
        text = text.replace(before, after)
        #print(text)

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

这个我也试过，结果一样

import re

with open('list.txt', 'r') as f:
    text = f.read()
    for k in d:
        before = f'.{k}(?!=\w)'
        print(before)
        after = f'.{d[k]}'
        print(after)
        text = re.sub(before, after, text)

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

Answer 1

你可以使用

import re

d = {'cancelled':'cancelled_at', 'deliver':'xxx'}
rx = re.compile(fr"(?<=\.)(?:{'|'.join(d)})\b")

with open('list.txt', 'r') as f:
    print( re.sub(rx, lambda x: d[x.group()], f.read()) )

参见 Python demo

代码生成的正则表达式看起来像

(?<=\.)(?:cancelled|deliver)\b

参见 regex demo .详情:

• (?<=\.) - 与紧跟在文字 . 之前的位置相匹配的正后视
• (?:cancelled|deliver) - 两种选择:cancelled或 deliver
• \b - 作为整个单词，\b是单词边界。

lambda x: d[x.group()]替换用相应的字典键值替换匹配的词。