如何用正则re按点分割字符串？多符号分割空串原因排查

Hey there! Let's tackle your regex questions step by step.

First off, remember that the English period (.) is a special character in regex—it matches any character except a newline. So to split on literal periods, you need to escape it or use a character class:

• Escape the period with a backslash: Use \ to tell regex you mean the literal dot.

  import re
  sample_text = "Hi there.This is a sentence.Another one here."
  split_result = re.split(r'\.', sample_text)
  # Output: ['Hi there', 'This is a sentence', 'Another one here', '']
  

  (Note: The final empty string is because the original text ends with a period—we'll cover how to handle that later!)

• Use a character class: Putting the period inside [] makes it a literal character, no escape needed.

  split_result = re.split(r'[.]', sample_text)
  # Same output as above
  

Great question—this happens for a few common reasons:

• Consecutive delimiters: If your string has back-to-back symbols (like Hello..World or Hey!,,There), regex splits between each symbol, leaving an empty string in the gap.
• Delimiters at the start/end: If your string starts or ends with a delimiter (like ...Hello or Test.), the split will create an empty string at the beginning or end.

How to fix it #

You have two solid options:

Option 1: Filter out empty strings after splitting

Just use a list comprehension to keep only non-empty entries:

text_with_multiple_symbols = "Hello..World!,,Test,,,"
split_raw = re.split(r'[.!,]', text_with_multiple_symbols)
clean_result = [s for s in split_raw if s]
# Output: ['Hello', 'World', 'Test']

Option 2: Adjust your regex to match consecutive delimiters

Use the + quantifier to match one or more consecutive delimiters—this treats them as a single split point, so no empty strings in between:

split_with_plus = re.split(r'[.!]+', text_with_multiple_symbols)
clean_result = [s for s in split_with_plus if s]
# Same clean output as above

Bonus: Use re.findall instead (even simpler!)

If you only care about the non-delimiter parts of the string, skip splitting entirely and use re.findall to match all sequences of characters not in your delimiter set:

result = re.findall(r'[^.!]+', text_with_multiple_symbols)
# Output: ['Hello', 'World', 'Test']

This automatically ignores empty strings since it only matches actual content.

内容的提问来源于stack exchange，提问作者Markus