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Python – Convert Strings to Uppercase in Dictionary value lists

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  • Last Updated : 01 Aug, 2020

Given dictionary with values list, convert all the strings to upper case.

Input : {“Gfg” : [“ab”, “cd”], “Best” : [“gh”], “is” : [“kl”]}
Output : {‘Gfg’: [‘AB’, ‘CD’], ‘Best’: [‘GH’], ‘is’: [‘KL’]}
Explanation : All value lists strings are converted to upper case.

Input : {“Gfg” : [“ab”, “cd”, “Ef”]}
Output : {‘Gfg’: [‘AB’, ‘CD’, “EF”]}
Explanation : All value lists strings are converted to upper case, already upper case have no effect.

Method #1 : Using dictionary comprehension + upper() + list comprehension

The combination of above functions can be used to solve this problem. In this, we perform upper case using upper(), list comprehension is used to iterate through all strings, dictionary comprehension is used to remake dictionary with upper case values.

Python3




# Python3 code to demonstrate working of 
# Convert Strings to Uppercase in Dictionary value lists
# Using dictionary comprehension + upper() + list comprehension
  
# initializing dictionary
test_dict = {"Gfg" : ["ab", "cd", "ef"],
             "Best" : ["gh", "ij"], "is" : ["kl"]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# using upper to convert to upper case 
res = {key: [ele.upper() for ele in test_dict[key] ] for key in test_dict }
  
# printing result 
print("The dictionary after conversion " + str(res)) 

Output

The original dictionary is : {‘Gfg’: [‘ab’, ‘cd’, ‘ef’], ‘Best’: [‘gh’, ‘ij’], ‘is’: [‘kl’]}
The dictionary after conversion {‘Gfg’: [‘AB’, ‘CD’, ‘EF’], ‘Best’: [‘GH’, ‘IJ’], ‘is’: [‘KL’]}

Method #2 : Using map() + upper() + dictionary comprehension

The combination of above functions can be used to solve this problem. In this, we perform the task of extending logic of upper case using map() instead of list comprehension.

Python3




# Python3 code to demonstrate working of 
# Convert Strings to Uppercase in Dictionary value lists
# Using map() + upper() + dictionary comprehension
  
# initializing dictionary
test_dict = {"Gfg" : ["ab", "cd", "ef"],
             "Best" : ["gh", "ij"], "is" : ["kl"]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# using map() to extend logic to all inner list 
res = {key: list(map(str.upper, test_dict[key])) for key in test_dict}
  
# printing result 
print("The dictionary after conversion " + str(res)) 

Output

The original dictionary is : {‘Gfg’: [‘ab’, ‘cd’, ‘ef’], ‘Best’: [‘gh’, ‘ij’], ‘is’: [‘kl’]}
The dictionary after conversion {‘Gfg’: [‘AB’, ‘CD’, ‘EF’], ‘Best’: [‘GH’, ‘IJ’], ‘is’: [‘KL’]}


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