Capturing a strings value in a regular expressions

guylikeme · 13-11-2015 08:45AM #1

Im analysing some output from a command in python

The output as follows

5 instance(s) updated

I want to extract the number before the rest of the string for later calculations and assign to a variable amount_of_instances but i don't know how to

Current code

commands[config.get_prop("app_get_all_attribute_values_for_mo").format(managed_object="Object1", attribute="Object2", value=Object3)] = {'contains': [" instance(s)"], 'cache_response': [{"amount_of_instances": r"\d+ instance(s)"}]}

CreepingDeath · 13-11-2015 09:53AM

You want a capture group and escape the round brackets.

(\d*)\sinstance\(s\)\supdated

You should be able to retrieve the number from the first/only capture group.

13-11-2015 11:21AM

I think you're overthinking this:

output = "5 instance(s) updated"
amount_of_instances = int(output.split()[0])

Assuming that the output of the program is always 1 or more digits followed by a space

Tar.Aldarion · 13-11-2015 02:39PM

[int(s) for s in str.split() if s.isdigit()]

or

re.findall(r'\d+', s)

or

int(s.split()[0])

Capturing a strings value in a regular expressions

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