Some one please help me in '?'metacharacter....@python

Answer 1

? makes elements optional.

solol?earn matches sololearn and soloearn, as l? makes 'l' optional.

You can also write:
solo(learn)? matching solo and sololearn

If you are referring to (?:...) something completely different is meant, namely group naming.

Answer 2

Technically, '?' stand for zero or one time, as '+' for one or many times, and '*' for zero or many times...
You can also specify the number of times or a range with curly brackets notation: {3} is 3 times, not less, not more, and {3,5} is from 3 to 5 times ^^

Answer 3

What is your question, Sir?

Answer 4

details of '?' metachatacter .