Why Does My Recursive Python Code Return None Despite Finding the Character?

Recursive Code Returns None: Understanding the Reason

The provided Python code aims to locate a specific character within a string using a recursive approach. However, it repeatedly returns None despite indicating its presence with the print statement 'i am here now.' To grasp the underlying reason behind this behavior, let's delve into the code's structure and uncover the source of its none returning nature.

The function isIn employs a divide-and-conquer strategy, partitioning the string aStr into equal segments and recursively searching the designated portion until it locates or eliminates the character. The print within the base case, 'i am here now,' serves as a confirmation of finding the character.

The omission of a return statement on the final line proves critical. When the function reaches the end of its execution trail without encountering an explicit return, it inherently defaults to returning None. This explains why True isn't returned upon successfully finding the character.

To remedy this issue, a return statement must be incorporated into the last line, as suggested by the solution:

<code class="python">return isIn(char, aStr)</code>

With this fix, the recursive function will appropriately propagate the True value when it stumbles upon the desired character in its recursive descent, guaranteeing the expected return and avoiding the default None response.

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