在 Python 中使用 RegEx 替换除一种特定模式之外的所有非字母数字字符

Question

Suppose, I have some text like

text = "xyz - aabc 123.56 cancer s15.2 date 12/03/2021 @ dd hospital www.someurl ocr.5rror 123.sometext"

Now, I want to create a regex that will replace any non-alphanumeric character with space except the dot(.) surrounded by digit, that is the final text should be like this

"xyz aabc 123.56 cancer s15.2 date 12 03 2021 dd hospital www someurl ocr 5rror 123 sometext"

I have this regex that can find these matches re.findall(r"(\\b[a-z0-9] \\d.\\d[a-z0-9] \\b)", text) gives me ['123.56', 's15.2'] , but I am not able to get the above text.

Thanks in advance.

Answer 1

You can use re.sub and a pattern with a capture group

(\d+(?:\.\d+))|\W+

The pattern matches:

• (\\d+(?:\\.\\d+)) Capture digits with an optional decimal part with a dot in group 1
• | OR
• \\W+ Match 1+ non word characters to replace with a single space (or use a negated character class [^a-zA-Z0-9]+ to keep matching an underscore)

In the replacement keep the capture group, and replace the match for 1+ non word characters with a space.

See a regex demo and a Python demo

import re

s = "xyz - aabc 123.56 cancer s15.2 date 12/03/2021 @ dd hospital www.someurl ocr.5rror 123.sometext"
pattern = r"(\d+(?:\.\d+))|\W+"
print(re.sub(pattern, lambda x: x.group(1) if x.group(1) else " ", s))

Output

xyz aabc 123.56 cancer s15.2 date 12 03 2021 dd hospital www someurl ocr 5rror 123 sometext