Fix KeyError: '\\s' when trying to replace a substring with one that includes special ch-CodePudding

import re

input_text = "Hello!, How are you? "

#input_text = re.sub(" ", r"[\s|-|]", input_text)
input_text, nro_repl = re.subn(' ', r'[\s|-|]', input_text)

print(repr(input_text))
print(repr(nro_repl))

The correct output:

4
'Hello!,[\s|-|]How[\s|-|]are[\s|-|]you?[\s|-|]'

The error that I get:

Traceback (most recent call last):
    this = chr(ESCAPES[this][1])
KeyError: '\\s'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
    raise s.error('bad escape %s' % this, len(this))
re.error: bad escape \s at position 1

How do I fix this error and get the desired result, managing to have the input string but making the replacements by substrings with the special characters?

CodePudding user response：

In the manual that @Nick posted it tells us that there will be no backslash escape processing of the replacement if we pass a function instead of a string. So all you have to do is replace the string argument with a lambda returning the string.

import re

input_text = "Hello!, How are you? "
input_text, nro_repl = re.subn(' ', lambda x: '[\s|-|]', input_text)

print(repr(nro_repl))
print(repr(input_text))

output:

4
'Hello!,[\\s|-|]How[\\s|-|]are[\\s|-|]you?[\\s|-|]'