从字符串 Python 中删除撇号（如果它们之前和/或之后有空格）

Question

I have a text:

text = "the march' which 'cause those it's good ' way"

I need to remove all apostrophes in the text if they have space before and/or after them:

"the march which cause those it's good way"

I tried:

re.sub("(?<=\b)'[a-z](?=\b)", "", text)

and

re.sub("\s'w+", " ", text)

But neither way seems to work for me

Answer 1

You can use replace() method of string to achieve this. As below:

text = "the march' which 'cause those it's good ' way"
new_text = text.replace("' "," ").replace(" ' "," ") 

Answer 2

You could get this done by contemplating the three different possibilities, and chaining them with | taking care of the order:

re.sub(r"(\s\'\s)|(\s\')|(\'\s)", ' ', text)
# "the march which cause those it's good way"

See demo

---

• (\s\'\s)|(\s\')|(\'\s)

  • 1st Alternative (\s\'\s)

    • 1st Capturing Group (\s\'\s)

    • \s matches any whitespace character (equal to [\r\n\t\f\v ] )

    • \' matches the character ' literally (case sensitive)
    • \s matches any whitespace character (equal to [\r\n\t\f\v ] )
  • 2nd Alternative (\s\')
    • 2nd Capturing Group (\s\')
    • \s matches any whitespace character (equal to [\r\n\t\f\v ] )
    • \' matches the character ' literally (case sensitive)
  • 3rd Alternative (\'\s)
    • 3rd Capturing Group (\'\s)
    • \' matches the character ' literally (case sensitive)
    • \s matches any whitespace character (equal to [\r\n\t\f\v ] )

Answer 3

Maybe...

(\s'\s?|'\s)

Given:

"the march' which 'cause those it's good ' way"

Replace with: a space, ie, " "

Output:

"the march which cause those it's good way"

Only 131 steps.

Demo: https://regex101.com/r/x04Vg1/1

Answer 4

Assuming you wish remove any extra spaces when a single quote surrounded by spaces is removed, you could use the following regular expression.

(?<= ) *' +|'(?= )|(?<= )'

Regex demo

import re
re.sub("(?<= ) *' +|'(?= )|(?<= )'", '', str)

Python demo

Python's regex engine performs the following operations.

(?<= )  # The following match must be preceded by a space  
 *      # match 0+ spaces
'       # match a single paren
 +      # match 1+ spaces
|       # or
'       # match a single paren
(?= )   # single paren must be followed by a space
|       # or
(?<= )  # The following match must be preceded by a space  
'       # match a single paren

(?<= ) is a postive lookbehind ; (?= ) is a postive lookahead .

Note that this causes problems with "Gus' gal" and "It 'twas the night before the big bowling match", where the single quotes should not be removed.