Topic: RegEx query

[Dumah]

I'm writing a quick regular expression in python to test an url path. I want it to look for a number of verbs and optionally pull out an integer:

Code: [Select]

pattern = r"/(?P<verb>view|edit|list|create|delete)(/(?P<id>\d{1,4})/)?"
paths = (
    "/view/1/",
    "/edit/15/",
    "/create/",
    "/list/",
    "/delete/2/",
    "/dummy/" #will not match
)

This pulls out the "verb" as well as an "id". Where there is no id it sets the group result to None. What I want is for the match to fail on paths that dont require an id (list, create) but to succeed on the others (view, edit,delete) and pull out the id.

Any ideas?

[ober]

I pretty much suck at regex and I've spent about 30 minutes in my life with Python, so I'm afraid I won't be of much help.

[Dumah]

No probs. I tried to use a negative lookback on the "id" section, but it seems that the python regex module will only apply a lookback if all the "verbs" I look back on are the same length.

For now I just added a bit of extra logic when the match is done....

[Dumah]

Current version seems to work, but any pitfalls or optimisations would be appreciated

Code: [Select]

^/\b(?P<verb>(?:(?:view|edit|delete)(?=/(?P<id>\d{1,4})))|create|list)\b/?