Return dictionary value as tuple or list from a string

You can create the dictionary with a nested dictionary-comprehension:

>>> data = """Xyz         pqrs,uvw
... Abc             foo,bar,blub"""
>>> d = {key: values.split(",") for key, values in 
            (line.split() for line in data.splitlines())}
>>> d
{'Xyz': ['pqrs', 'uvw'], 'Abc': ['foo', 'bar', 'blub']}

Then check containment with any:

>>> any("pqrs" in v for v in d.values())
True

Update: Since you seem to be using Python 2.6, before the existence of dict-comprehensions, you'll have to use this equivalent form:

>>> d = dict((key, values.split(",")) for key, values in 
             (line.split() for line in data.splitlines()))

You have to clarify your rules. But from what you've shown us this regular expression should do the job

import re
pattern = re.compile(r'[\s,]*')
result = {}
for line in data.strip().splitlines():
    parts = pattern.split(line)
    key = parts[0]
    values = parts[1:]
    if 'pqrs' in values:
        print 'yes'
    result[key] = values