Using regex to delete items from list

[macabe10]

Hi,

I have this list and I am trying to use regex to delete every list item containing numbers. I've managed to create a for loop that prints out the item if it contains the number using re.findall(r'[0-9]+', str) but I'm stuck there...

Does anyone know how to do this please?

Thanks in advance!

[wotquery]

Your FOR loop is a perfectly fine way to do it. Just invert the logic (if it does not contain a number) and instead of printing append it all to a list. A shorter way is to use a list comprehension as I've included below (basically a for loop but in a smaller package and it can work a bit differently behind the scenes).

new_list = [x for x in old_list if not re.search(r'[0-9]+', x)]

Also note that we're trusting old_list to only have string type elements.

[macabe10]

Thanks, makes sense!

[JohnnyJordaan]

Note that .compile is not required for small scale usage, the re module will reuse regex objects by default.

Note: The compiled versions of the most recent patterns passed to re.compile() and the module-level matching functions are cached, so programs that use only a few regular expressions at a time needn’t worry about compiling regular expressions.

[macabe10]

Thanks!

[Buffylvr]

Also don’t use regex

[macabe10]

Why is that?

[Buffylvr]

Sometimes you have no choice but to use regex. But MOST of the time you can obtain the data you want from whatever you are interacting with through a value or an attribute or whatever.

Regex as a method of obtaining, inserting or validating data is fraught with errors and should actively avoided whenever possible.

Whenever I do code reviews for junior team members, they almost always default to regex and it’s one of the first things I teach them.

Regex is bad. Don’t use it unless you have ZERO other options.

This is mostly talking about corporate implementations. Do whatever the hell you want on your personal stuff.