Python | Initializing dictionary with list index-values

Last Updated : 26 Aug, 2019

While working with Python we might need to perform tasks in which we need to assign a dictionary with list values as dictionary values and index as dictionary keys. This type of problem is quite common in cases we need to perform data-type conversion. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using dictionary comprehension + len()

This task can be performed using the combination of above functions in which we perform the construction of dictionary using the dictionary comprehension and indexing the limited using the len function.

# Python3 code to demonstrate working of 
# Initializing dictionary with list index-values 
# Using dictionary comprehension + len() 
  
# initializing list 
test_list = ['Gfg', 'is', 'best'] 
  
# printing original list 
print("The original list is : " + str(test_list)) 
  
# Initializing dictionary with list index-values 
# Using dictionary comprehension + len() 
res = {x : test_list[x] for x in range(len(test_list))} 
  
# printing result 
print("The dictionary indexed as list is :  " + str(res)) 

Output :

The original list is : ['Gfg', 'is', 'best']
The dictionary indexed as list is :  {0: 'Gfg', 1: 'is', 2: 'best'}

Method #2 : Using dict() + enumerate()

The combination of these methods can also be used to perform this task. In this we use the quality of enumerate function to get the indices and dict() is used to convert the list to dictionary.

# Python3 code to demonstrate working of 
# Initializing dictionary with list index-values 
# Using dict() + enumerate() 
  
# initializing list 
test_list = ['Gfg', 'is', 'best'] 
  
# printing original list 
print("The original list is : " + str(test_list)) 
  
# Initializing dictionary with list index-values 
# Using dict() + enumerate() 
res = dict(enumerate(test_list)) 
  
# printing result 
print("The dictionary indexed as list is :  " + str(res)) 

Output :

The original list is : ['Gfg', 'is', 'best']
The dictionary indexed as list is :  {0: 'Gfg', 1: 'is', 2: 'best'}

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