Your for-loop might be missing an else block (Python 3)

Your for-loop might be missing an else block

There's a little-known construct in Python that can be quite useful: using else in combination with loops. That's right, for-loops and while-loops can be followed by an else block! Let's look at how you can use the else block in combination with a for-loop.

When is this else block executed?

The else block is executed as soon as:

  • Your for-loop is out of elements
  • The expression in your while becomes False

With this exception: when you exit the loop with a break or a return, the else block will be skipped.

When to use?

Whenever you find yourself using a flag inside a loop, e.g., a boolean variable like found, you can probably use else instead.

In this crumb, we check if the letter 'Q' is in the variable name using a loop. (Yes, I know, there's a better way!) Instead of using a flag like found to print the fact that a 'Q' was not found, we use else.

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