Python: Return every element that exists in any of the two given lists once, after applying function to each element of both
Python List: Exercise - 228 with Solution
Write a Python program to get every element that exists in any of the two given lists once, after applying the provided function to each element of both.
- Create a set by applying fn to each element in x.
- Use a list comprehension in combination with fn on y to only keep values not contained in the previously created set, _x.
- Finally, create a set from the previous result and x and transform it into a list.
Sample Solution:
Python Code:
def union_by_el(x, y, fn):
_x = set(map(fn, x))
return list(set(x + [item for item in y if fn(item) not in _x]))
from math import floor
print(union_by_el([4.1], [2.2, 4.3], floor))
Sample Output:
[2.2, 4.1]
Flowchart:

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Previous: Write a Python program to get the symmetric difference between two lists, after applying the provided function to each list element of both.
Next: Write a Python program to find the index of the first element in the given list that satisfies the provided testing function.
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Python: Tips of the Day
Decapitalizes the first letter of a string:
Example:
def tips_decapitalize(s, upper_rest=False): return s[:1].lower() + (s[1:].upper() if upper_rest else s[1:]) print(tips_decapitalize('PythonTips')) print(tips_decapitalize('PythonTips', True))
Output:
pythonTips pYTHONTIPS
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