list or dictionary

[Ganesh Pal]

Thanks Steve  for the clues , quickly tried  out # Version 1 doesn't seen
to work.


>>> for line in hostname:
...     regex = r'(.*) is array with id {}'.format(devid)
...     mo = re.search(regex, line)
...     print line, regex, mo
...     if mo is not None:
...         print mo.group(1)
...
RX-145-1 is array id 1 (.*) is array with id 3 None
RX-145-2 is array id 2 (.*) is array with id 3 None
RX-145-3 is array id 3 (.*) is array with id 3 None
>>> hostname
['RX-145-1 is array id 1', 'RX-145-2 is array id 2', 'RX-145-3 is array id
3']
>>> type(devid)
<type 'int'>
>>> devid
3
---------------------------------------------------------------------------------------------------
>>> devid = '3'
>>> for line in hostname:
...     regex = r'(.*) is array with id {}'.format(devid)
...     mo = re.search(regex, line)
...     print line, regex, mo
...     if mo is not None:
...        print mo.group(1)
...
RX-145-1 is array id 1 (.*) is array with id 3 None
RX-145-2 is array id 2 (.*) is array with id 3 None
RX-145-3 is array id 3 (.*) is array with id 3 None
>>> type(devid)
<type 'str'>
----------------------------------------------------------------------------------------------
>>> for line in hostname:
...     regex = r'(.*) is array with id %d' % (devid)
...     mo = re.search(regex, line)
...     print line, regex, mo
...     if mo is not None:
...        print mo.group(1)
...
RX-145-1 is array id 1 (.*) is array with id 3 None
RX-145-2 is array id 2 (.*) is array with id 3 None
RX-145-3 is array id 3 (.*) is array with id 3 None
---------------------------------------------------------------------------------------------------

Looks like Iam missing something ?



Regards,
Ganesh


On Wed, Sep 21, 2016 at 5:57 AM, Steve D'Aprano <steve+python at pearwood.info>
wrote:

> On Wed, 21 Sep 2016 04:04 am, Ganesh Pal wrote:
>
> > I am on python 2.7 and Linux
> >
> > I have the stdout in the below form , I need to write a function to get
> > hostname for the given id.
> >
> >
> > Example:
> >
> >>>> stdout
> > 'hostname-1 is array with id 1\nhostname-2 is array with  id
> 2\nhostname-3
> > is array with id 3\n'
> >
> >
> > def get_hostname(id)
> >        return id
> >
> > what's a better option here
> >
> > 1. store it in list and grep for id and return
> > 2. store it in dict as key and value i.e hostname = { 'hostname1': 1} and
> > return key
> > 3. any other simple options.
>
>
> Why don't you write a function for each one, and see which is less work?
>
> # Version 1: store the hostname information in a list as strings
>
> hostnames = ['hostname-1 is array with id 1',
>              'hostname-2 is array with id 2',
>              'hostname-842 is array with id 842']
>
> def get_hostname(id):
>     for line in hostnames:
>         regex = r'(.*) is array with id %d' % id
>         mo = re.match(regex, line)
>         if mo is not None:
>             return mo.group(1)
>     raise ValueError('not found')
>
>
> # Version 2: store the hostname information in a dict {hostname: id}
>
> hostnames = {'hostname1': 1, 'hostname2': 2, 'hostname842': 842}
>
> def get_hostname(id):
>     for key, value in hostnames.items():
>         if value == id:
>             return key
>     raise ValueError('not found')
>
>
> # Version 3: use a dict the way dicts are meant to be used
>
> hostnames = {1: 'hostname1', 2: 'hostname2', 842: 'hostname842'}
>
> def get_hostname(id):
>     return hostnames[id]
>
>
>
>
>
>
>
>
> --
> Steve
> “Cheer up,” they said, “things could be worse.” So I cheered up, and sure
> enough, things got worse.
>
> --
> https://mail.python.org/mailman/listinfo/python-list
>