如何使用正则表达式删除字符串的一个非常特定的部分：

I was wondering how I can use regex to remove a specific portion of a string. For example, I have a list that looks like this:

我想知道如何使用正则表达式删除字符串的特定部分。例如，我有一个如下所示的列表：

name=derek;
name=derek.1;
name=derek.2; 
name=derek.3;
name=ophelia;
name=ophelia.1;
name=ophelia.2;
name=ophelia.3;

I want to replace the characters after 'name=' and between either the '.' if present or the ';' at the end of the line. The output should look like this list:

我想替换'name ='之后和'。'之间的字符。如果存在或';'在行尾。输出应该如下所示：

name=apple;
name=apple.1;
name=apple.2; 
name=apple.3;
name=apple;
name=apple.1;
name=apple.2;
name=apple.3;

2 个解决方案

#1

You need a multiline regex for this:

你需要一个多行正则表达式：

>>> print(s)
name=derek;
name=derek.1;
name=derek.2; 
name=derek.3;
name=ophelia;
name=ophelia.1;
name=ophelia.2;
name=ophelia.3;
>>> replace_with = r'\1{0}\2'.format('apple')  # preserve start & end
                                               # replace only the middle
>>> regex = '^(name=)[^\.;]+(.*)$'
>>> replaced = re.sub(regex,                # pattern
...                   replace_with,         # replacement
...                   s,                    # an original multiline string
...                   flags=re.MULTILINE);  # regex for multiple lines
>>> print(replaced)
name=apple;
name=apple.1;
name=apple.2; 
name=apple.3;
name=apple;
name=apple.1;
name=apple.2;
name=apple.3;

#2

This isn't exactly what you asked for, but here's a version that doesn't need regex at all:

这不是你要求的，但这里的版本根本不需要正则表达式：

s = """name=derek;
name=derek.1;
name=derek.2; 
name=derek.3;
name=ophelia;
name=ophelia.1;
name=ophelia.2;
name=ophelia.3;"""

lines = s.split("\n")
updated = []
for line in lines:
    left, right = line.split("=")
    if "." in right:
        new_right = "apple." + right.split(".")[1]
    else:
        new_right = "apple;"
    updated.append(left + "=" + new_right)

print "\n".join(updated)

#1