creating a separate list in python

Question

I have a multiple list created as

[['Mappings_1:', 'AMA111:AMA112,EM5', 'EM3,EM4',
  'EM1,EM2'],
 ['Mappings_2:', 'AMA111:AMA112,EM5', 'EM3,EM4'],
 ['Mappings_3:', 'AMA111:AMA112,EM5', 'EM3,EM4',
  'EM1,EM2', 'FPA1,FPA1', 'FPA3:FPA4,AMA113']]

I have one selection parameter that can hold a value as 'Mappings_1' or 'Mappings_2' or 'Mappings_3',

If value is 'Mappings_1' then I want to separate the ['Mappings_1:', 'AMA111:AMA112,EM5', 'EM3,EM4', 'EM1,EM2'] in a separate list by assign Id as shown below

valid_map = [{'Id': '1', 'mapping': 'AMA111:AMA112,EM5'},
             {'Id': '2', 'mapping': 'EM3,EM4'},
             {'Id': '3', 'mapping': 'EM1,EM2'}]

Based on selected parameter, I need to separate the particular list by assign channel id.

Please share some idea

Post the code you have so far - I think it will help us understand what you're trying to do. — Chris Martin
– Chris Martin, Commented Jun 12, 2014 at 7:05

senshin · Accepted Answer · 2014-06-12 07:05:21Z

This is pretty straightforward - step over each sublist in your list, check which one has the same first element as your selection parameter (e.g. Mappings_1), and then convert the rest of that sublist into a list of dictionaries.

def list_to_mapping(lst, selection):
    for sublst in lst: # step over sublists
        if sublst[0] == selection: # if selection parameter matched
            # build list of dictionaries
            valid_map = [{'id': index+1, 'mapping': value} # index+1 for 1-based indexing
                         for index, value in enumerate(sublst[1:])]
            return valid_map

lst = [['Mappings_1:', 'AMA111:AMA112,EM5', 'EM3,EM4', 'EM1,EM2'],
       ['Mappings_2:', 'AMA111:AMA112,EM5', 'EM3,EM4'],
       ['Mappings_3:', 'AMA111:AMA112,EM5', 'EM3,EM4', 'EM1,EM2', 'FPA1,FPA1', 'FPA3:FPA4,AMA113']]

result = list_to_mapping(lst, 'Mappings_1:')
print(result)

Result (formatted):

[{'mapping': 'AMA111:AMA112,EM5', 'id': 1}, 
 {'mapping': 'EM3,EM4', 'id': 2}, 
 {'mapping': 'EM1,EM2', 'id': 3}]

Pokey McPokerson · Accepted Answer · 2014-06-12 07:11:12Z

1

Do you have control over the original list generation? Maybe you should rather use a dictionary.

Something like:

valid_maps = {'Mappings_1': ['AMA111:AMA112,EM5', 'EM3,EM4', 'EM1,EM2'],
              'Mappings_2': ['AMA111:AMA112,EM5', 'EM3,EM4'],
              'Mappings_3': ['AMA111:AMA112,EM5', 'EM3,EM4','EM1,EM2', 
                             'FPA1,FPA1', 'FPA3:FPA4,AMA113']}

I used lists as the values in the dictionary, since the 'id' tags don't seem to add much.

answered Jun 12, 2014 at 7:11

Pokey McPokerson

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Comments

ugursogukpinar · Accepted Answer · 2014-06-12 07:19:13Z

I think your multiple list is not efficient. You should use dict. But you can try something like that.

#!/usr/bin/env python
#-*-coding:utf-8-*-



multiple_list = [
                    ['Mappings_1', 'AMA111:AMA112,EM5', 'EM3,EM4','EM1,EM2'],
                    ['Mappings_2', 'AMA111:AMA112,EM5', 'EM3,EM4'],
                    ['Mappings_3', 'AMA111:AMA112,EM5', 'EM3,EM4','EM1,EM2', 'FPA1,FPA1', 'FPA3:FPA4,AMA113']
                ]

valid_map = []
selection = "Mappings_1"
i = 0

while((i < len(multiple_list)) and (multiple_list[i][0]!= selection)):
    print multiple_list[i][0]
    i += 1

if(i<len(multiple_list)):
    j = 1
    while(j<len(multiple_list[i])):
        tmpDict = dict()
        tmpDict['id'] = j
        tmpDict['mapping']  = multiple_list[i][j]
        valid_map.append(tmpDict)
        j += 1




print valid_map

But my suggestion change your data model.

#!/usr/bin/env python
#-*-coding:utf-8-*-



multiple_list = {
                    'Mappings_1' : ['AMA111:AMA112,EM5', 'EM3,EM4','EM1,EM2'],
                    'Mappings_2' : ['AMA111:AMA112,EM5', 'EM3,EM4'],
                    'Mappings_3' : ['AMA111:AMA112,EM5', 'EM3,EM4','EM1,EM2', 'FPA1,FPA1', 'FPA3:FPA4,AMA113']
                }

valid_map = []
selection = 'Mappings_1'

if(selection in multiple_list):
    for i in xrange(0,len(multiple_list[selection])):
        tmpDict = {}
        tmpDict["id"] = i + 1
        tmpDict["mapping"] = multiple_list[selection][i]
        valid_map.append(tmpDict)
        i += 1


print valid_map

namit · Accepted Answer · 2014-06-12 07:23:01Z

0

In [1]: data = [['Mappings_1:', 'AMA111:AMA112,EM5', 'EM3,EM4',   'EM1,EM2'],  ['Mappings_2:', 'AMA111:AMA112,EM5', 'EM3,EM4'],  ['Mappings_3:', 'AMA111:AM
A112,EM5', 'EM3,EM4',   'EM1,EM2', 'FPA1,FPA1', 'FPA3:FPA4,AMA113']]

In [2]: result = {x[0]:[{"id": y[0], "mapping":y[1]} for y in list(enumerate(x))[1:]] for x in data}                                                       

In [3]: result["Mappings_1:"]                                                                                                                              
Out[3]: 
[{'id': 1, 'mapping': 'AMA111:AMA112,EM5'},
 {'id': 2, 'mapping': 'EM3,EM4'},
 {'id': 3, 'mapping': 'EM1,EM2'}]

answered Jun 12, 2014 at 7:23

namit

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