I've list like this.

list=[[['name1','name2'],[n1,n2]], [['name3','name4'],[n3,n4]]]

I want to get n1 if input is name1

similarly if input if name3 then output should be n3

Note: name1-Type str
      n1-   Type int

Is there is any way to do this?..Pls suggest me solution/Solution steps that i can follow to solve this issue..

CodePudding user response：

I see building an intermediate lookup dict from my_list, then looking up as you like:

my_list=[
  [['name1','name2'],['n1','n2']], 
  [['name3','name4'],['n3','n4']]
]

lookup = {}

for double_tuple in my_list:
    lhs, rhs = double_tuple
    zipped = zip(lhs, rhs)  # ['name1','name2'],['n1','n2'] → ['name1', 'n1'],['name2','n2']
    lookup.update(dict(zipped))

print(lookup['name1'])  # → 'n1'

CodePudding user response：

It can be easily solved with a list comprehension:

1. unpack the elements in the list
2. filter for k1 == input
3. get first result, if exists

input_ = "name1"
list_ = [[['name1','name2'],[n1,n2]], [['name3','name4'],[n3,n4]]]
candidates = [v1 
              for (k1, _), (v1, _) in list_
              if k1 == input_]
if len(candidates) == 0:
    print("No such key: "   input_)
else:
    print("Value is "   candidates[0])

Note: I used trailing underscores in the names to avoid overwriting builtin functions (list and input). Overwriting builtin functions is bad practice.

CodePudding user response：

You can use filter combined with next:

def get_item_from_key(input_list, key):
    """Return item corresponding to a specific key"""
    try:
        return next(filter(lambda x: x[0][0] == key, input_list))[1][0]
    except StopIteration:
        return None

So, if the input list is a = [[['name1', 'name2'], [0, 1]], [['name3', 'name4'], [2, 3]]], you can ask for any key you are interested into:

get_item_from_key(a, 'name1')  # this will return 0
get_item_from_key(a, 'name3')  # this will return 2
get_item_from_key(a, 'name2')  # this will return None
get_item_from_key(a, 'name5')  # this will return None

CodePudding user response：

Similar to @Zach Young's answer, you can create a list of dictionaries by zipping pairs and using the dict constructor from the sublists. Then using collections.ChainMap, create a single view.

from collections import ChainMap
dct = ChainMap(*[dict(zip(*sublist)) for sublist in lst])

Then

>>> print(dct['name1'])
n1

>>> print(dct['name3'])
n3