What is the purpose of the colon before a block in Python?

Question

What is the purpose of the colon before a block in Python?

Example:

if n == 0:
    print \"The end\"

Answer 1

According to Guido Van Rossum, the Python inventor, the idea of using a colon to make the structure more apparent is inspired by earlier experiments with a Python predecessor, ABC language, which also targeted the beginners. Apparently, on their early tests, beginner learners progressed faster with colon than without it. Read the whole story at Guido's post python history blog.

http://python-history.blogspot.com/2009/02/early-language-design-and-development.html

And yes, the colon is useful in one-liners and is less annoying than the semicolon. Also style guide for long time recommended break on several lines only when it ends with a binary operator

x = (23 + 
     24 + 
     33)

Addition of colon made compound statement look the same way for greater style uniformity.

There is a 'colonless' encoding for CPython as well as colon-less dialect, called cobra. Those did not pick up.