Remove some characters from a string

[Julien]

Hi,

I can't seem to find the right regular expression to achieve what I
want. I'd like to remove all characters from a string that are not
numbers, letters or underscores.

For example:
str: 'si_98udasgf'

Would you have any hint?

Thanks a lot!

Julien

 

[Chris]

Hi,

I can't seem to find the right regular expression to achieve what I
want. I'd like to remove all characters from a string that are not
numbers, letters or underscores.

For example:


str: 'si_98udasgf'

Would you have any hint?

Thanks a lot!

Julien

One quick and dirty way would be...

import string
safe_chars = string.ascii_letters + string.digits + '_'
test_string = 'si_98%u^[email protected]*gf'
''.join([char if char in safe_chars else '' for char in test_string])

you could also use a translation table, see string.translate (the
table it uses can be made with string.maketrans)

 

[Paul Hankin]

Hi,

I can't seem to find the right regular expression to achieve what I
want. I'd like to remove all characters from a string that are not
numbers, letters or underscores.

For example:


str: 'si_98udasgf'

For speed, you can use 'string.translate', but simplest is to use a
comprehension:

import string

def magic_function(s, keep=string.ascii_letters + string.digits +
'_'):
return ''.join(c for c in s if c in keep)

 

[Fredrik Lundh]

I can't seem to find the right regular expression to achieve what I
want. I'd like to remove all characters from a string that are not
numbers, letters or underscores.

For example:

str: 'si_98udasgf'

the easiest way is to replace the things you don't want with an empty
string:
'si_98udasgf'

("\W" matches everything that is "not numbers, letters, or underscores",
where the alphabet defaults to ASCII. to include non-ASCII letters, add
"(?u)" in front of the expression, and pass in a Unicode string).

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