zip

zip function:

• sequences are passed to function

• zip returns an iterator with tuples in which n-tuple consists of n-elements of sequences that have been passed as arguments

• for example, 10th tuple will contain 10th element of each of passed sequences

• if sequences with different lengths have been passed to input, they will all be cut by the shortest sequence

• the order of elements is respected

Note

Since zip is an iterator, list is used to show its contents

Example of using zip:

In [1]: a = [1, 2, 3]

In [2]: b = [100, 200, 300]

In [3]: list(zip(a, b))
Out[3]: [(1, 100), (2, 200), (3, 300)]

Use zip with lists of different lengths:

In [4]: a = [1, 2, 3, 4, 5]

In [5]: b = [10, 20, 30, 40, 50]

In [6]: c = [100, 200, 300]

In [7]: list(zip(a, b, c))
Out[7]: [(1, 10, 100), (2, 20, 200), (3, 30, 300)]

Using zip to create a dictionary

Example of using zip to create a dictionary:

In [4]: d_keys = ['hostname', 'location', 'vendor', 'model', 'IOS', 'IP']
In [5]: d_values = ['london_r1', '21 New Globe Walk', 'Cisco', '4451', '15.4', '10.255.0.1']

In [6]: list(zip(d_keys, d_values))
Out[6]:
[('hostname', 'london_r1'),
 ('location', '21 New Globe Walk'),
 ('vendor', 'Cisco'),
 ('model', '4451'),
 ('IOS', '15.4'),
 ('IP', '10.255.0.1')]

In [7]: dict(zip(d_keys, d_values))
Out[7]:
{'IOS': '15.4',
 'IP': '10.255.0.1',
 'hostname': 'london_r1',
 'location': '21 New Globe Walk',
 'model': '4451',
 'vendor': 'Cisco'}
In [8]: r1 = dict(zip(d_keys, d_values))

In [9]: r1
Out[9]:
{'IOS': '15.4',
 'IP': '10.255.0.1',
 'hostname': 'london_r1',
 'location': '21 New Globe Walk',
 'model': '4451',
 'vendor': 'Cisco'}

In example below there is a separate list which stores keys and a dictionary which stores information about each device in form of list (to preserve order).

Collect them in dictionary with keys from list and information from dictionary data:

In [10]: d_keys = ['hostname', 'location', 'vendor', 'model', 'IOS', 'IP']

In [11]: data = {
   ....: 'r1': ['london_r1', '21 New Globe Walk', 'Cisco', '4451', '15.4', '10.255.0.1'],
   ....: 'r2': ['london_r2', '21 New Globe Walk', 'Cisco', '4451', '15.4', '10.255.0.2'],
   ....: 'sw1': ['london_sw1', '21 New Globe Walk', 'Cisco', '3850', '3.6.XE', '10.255.0.101']
   ....: }

In [12]: london_co = {}

In [13]: for k in data.keys():
   ....:     london_co[k] = dict(zip(d_keys, data[k]))
   ....:

In [14]: london_co
Out[14]:
{'r1': {'IOS': '15.4',
  'IP': '10.255.0.1',
  'hostname': 'london_r1',
  'location': '21 New Globe Walk',
  'model': '4451',
  'vendor': 'Cisco'},
 'r2': {'IOS': '15.4',
  'IP': '10.255.0.2',
  'hostname': 'london_r2',
  'location': '21 New Globe Walk',
  'model': '4451',
  'vendor': 'Cisco'},
 'sw1': {'IOS': '3.6.XE',
  'IP': '10.255.0.101',
  'hostname': 'london_sw1',
  'location': '21 New Globe Walk',
  'model': '3850',
  'vendor': 'Cisco'}}