Flatten a list X91996


Statement
 

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Write a program that prints every given list flattened. For example, [[[a]],b][[[a]], b] flattened is [a,b][a, b], and [[a,b],[c,d]][[a, b], [c, d]] flattened is [a,b,c,d][a, b, c, d].

Define and use a recursive function

flatten(t)

that flattens a list tt.

Hint

Using the @ast@ package, you can extract the list tt encoded in a string ss with @t = ast.literal_eval(s)@.

Input

The input consists of several lists.

Output

Print every given list flattened.

Public test cases

  • Input

    []
['a']
[['a']]
[[['a']]]
['a', 'b']
['a', []]
[[], 'a']
[['a'], 'b']
['a', ['b']]
[[['a']], 'b']
['a', [['b']]]
[['a', 'b'], ['c', 'd']]

    Output

    []
['a']
['a']
['a']
['a', 'b']
['a']
['a']
['a', 'b']
['a', 'b']
['a', 'b']
['a', 'b']
['a', 'b', 'c', 'd']
    • Information
    Author
    Gabriel Valiente
    Language
    English
    Official solutions
    Python
    User solutions
    Python