Python Coding challenge - Day 674| What is the output of the following Python Code?

 

Code Explanation:

Function definition (evaluated once)

def tricky(val, lst=[]): defines a function with a default list.

That default list is created once at definition time and reused on later calls if you don’t pass lst.

Function body (what each call does)

lst.append(val): mutates the list in-place by adding val.

return sum(lst): returns the sum of all numbers currently in lst.

First call: tricky(10)

No lst passed → uses the shared default list (currently []).

After append: lst becomes [10].

sum([10]) → 10.

Result: 10 (and the shared default list now holds [10]).

Second call: tricky(20)

Still no lst passed → uses the same shared list (now [10]).

After append: lst becomes [10, 20].

sum([10, 20]) → 30.

Result: 30 (shared list is now [10, 20]).

Third call: tricky(30, [1])

An explicit list [1] is provided → not the shared default.

After append: list becomes [1, 30].

sum([1, 30]) → 31.

Result: 31 (this separate list is discarded after the call unless stored elsewhere).

Final print

Prints the three return values separated by spaces.

Output:

10 30 31

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