Python list split

Question

I would like to keep only name and value ( key value pair ) This is list.

[{u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u'c_user',
  u'path': u'/',
  u'secure': True,
  u'value': u'100001724251788'},
 {u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u'csm',
  u'path': u'/',
  u'secure': False,
  u'value': u'2'},
 {u'domain': u'.facebook.com',
  u'expiry': 1441116441,
  u'name': u'datr',
  u'path': u'/',
  u'secure': False,
  u'value': u'AUojUqoBUYA2wj4j04GT5XvX'},
 {u'domain': u'.facebook.com',
  u'expiry': 1441116442,
  u'name': u'lu',
  u'path': u'/',
  u'secure': False,
  u'value': u'RitwQJMNRJ8siUh_9eIj4SMw'},
 {u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u's',
  u'path': u'/',
  u'secure': True,
  u'value': u'Aa7ebY1RvmeilCX8.BSI0od'},
 {u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u'xs',
  u'path': u'/',
  u'secure': True,
  u'value': u'62%3AjNm_3ySkegf7cg%3A2%3A1378044445%3A10945'},
 {u'domain': u'.facebook.com',
  u'expiry': 1380636479,
  u'name': u'fr',
  u'path': u'/',
  u'secure': False,
  u'value': u'0aU8cfDygWXo1ETQA.AWV9BQIzKARYURFpuxUdXLoXcl8.BSI0od.j_.FIj.AWXjyq2t'},
 {u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u'sub',
  u'path': u'/',
  u'secure': False,
  u'value': u'64'},
 {u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u'p',
  u'path': u'/',
  u'secure': False,
  u'value': u'125'},
 {u'domain': u'.facebook.com',
  u'expiry': None,
  u'name': u'presence',
  u'path': u'/',
  u'secure': True,
  u'value': u'EM378046939EuserFA21B01724251788A2EstateFDsb2F0Et2F_5b_5dElm2FnullEuct2F1378043847BEtrFnullEtwF2448105081EatF1378046499377G378046939504CEchFDp_5f1B01724251788F13CC'}]
[Dbg]>>> type(cookies)
<type 'list'>
[Dbg]>>> newlist = [{'domain': i['domain'], 'name': i['name'], 'value': i['value']} for i in cookies]
[Dbg]>>> newlist
[{'domain': u'.facebook.com', 'name': u'c_user', 'value': u'100001724251788'},
 {'domain': u'.facebook.com', 'name': u'csm', 'value': u'2'},
 {'domain': u'.facebook.com',
  'name': u'datr',
  'value': u'AUojUqoBUYA2wj4j04GT5XvX'},
 {'domain': u'.facebook.com',
  'name': u'lu',
  'value': u'RitwQJMNRJ8siUh_9eIj4SMw'},
 {'domain': u'.facebook.com',
  'name': u's',
  'value': u'Aa7ebY1RvmeilCX8.BSI0od'},
 {'domain': u'.facebook.com',
  'name': u'xs',
  'value': u'62%3AjNm_3ySkegf7cg%3A2%3A1378044445%3A10945'},
 {'domain': u'.facebook.com',
  'name': u'fr',
  'value': u'0aU8cfDygWXo1ETQA.AWV9BQIzKARYURFpuxUdXLoXcl8.BSI0od.j_.FIj.AWXjyq2t'},
 {'domain': u'.facebook.com', 'name': u'sub', 'value': u'64'},
 {'domain': u'.facebook.com', 'name': u'p', 'value': u'125'},
 {'domain': u'.facebook.com',
  'name': u'presence',
  'value': u'EM378046939EuserFA21B01724251788A2EstateFDsb2F0Et2F_5b_5dElm2FnullEuct2F1378043847BEtrFnullEtwF2448105081EatF1378046499377G378046939504CEchFDp_5f1B01724251788F13CC'}]

To:

    <Cookie>.facebook.com:datr:gyenULkNKjCIJFTYDz2qbp9I
    <Cookie>.facebook.com:c_user:120004707330532
    <Cookie>.facebook.com:fr:0LglznOeWFepXcvAF.AWVm9awu51UtdvT65f9HqxYXUsI.BQp4ej._Q.AAA.AWW8GKGl
    <Cookie>.facebook.com:lu:gg1dq7zzNjC6pd7W9W0SFHnA
    <Cookie>.facebook.com:s:Aa5Zmp1zeLF36x3s
    <Cookie>.facebook.com:xs:1%3AWvWR_uXSzC3p3w%3A0%3A1374938392
    <Cookie>

But your output also has one instance of domain and expiry, not just name and value. — interjay
– interjay, Commented Sep 1, 2013 at 15:03
In your example you're also keeping the "domain" and "expiry" keys as well. What is it you're after? — Mark R. Wilkins
– Mark R. Wilkins, Commented Sep 1, 2013 at 15:04
@MarkR.Wilkins, thank again. What i am trying to do this. Represent my data in format ( updated just now ). But i am confused how to sort and reprent data as string like that. — FastestWebServerYet
– FastestWebServerYet, Commented Sep 1, 2013 at 15:39

jfs · Accepted Answer · 2013-09-01 15:20:28Z

5

To extract arbitrary names from a list of dictionaries, you could use operator.itemgetter():

from operator import itemgetter

names = ["name", "value"] # fields to extract
values = itemgetter(*names) # function that extracts values from an input dict

result = [dict(zip(names, values(d))) for d in list_of_dicts]
print(result)

Output

[{'name': u'c_user', 'value': u'100001456251788'},
 {'name': u'csm', 'value': u'2'},
 {'name': u'datr', 'value': u'AUojdfkBUYA2wj4j04GT5XvX'}]

answered Sep 1, 2013 at 15:20

jfs

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2 Comments

FastestWebServerYet Over a year ago

how to remove u' from all this?

Mark R. Wilkins Over a year ago

The return value doesn't actually contain u'. That's just an indication that those are unicode strings, which you specified in your question.

Mark R. Wilkins · Accepted Answer · 2013-09-01 15:13:23Z

You can use what's called a "list comprehension" to cull out the key/value pairs you want:

new_list = [{'name':x['name'], 'value':x['value']} for x in list]

A little extra explanation: What this does is loop over the entries in list, assigning each to x, then applying that value in the expression that comes at the front, in this case

{'name':x['name'], 'value':x['value']}

This can be a quick way to cull elements you want out of a more comprehensive list or to make a new list that you can define with a simple expression from the elements of an existing list.

It's also possible to do the same thing to make a new dictionary by replacing the outer square brackets [] with curly brackets {}.

Also: If you are making your new list to feed to a loop, and your original data set is quite large, you can make a "generator", which is a thing like a list that you can loop over but that doesn't store the new subset of data in memory. Making a generator replaces the square brackets [] with parentheses ().

new_generator = ({'name':x['name'], 'value':x['value']} for x in list)
for element in new_generator:
    ... do whatever ...

This avoids duplicating large amounts of data in memory and only computes each element as the loop proceeds.

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