Question

Construct an algorithm[as comment lines] and write a python program to create a regular expression to retrieve all words starting with input1 or ending with input2 in each string.
For example:

Test Input

An apple for a day keeps the doctor away
a
y

Result

An
apple
a
away
day
away

Answer 1

Answer:

\ Used to drop the special meaning of character following it

[] Represent a character class

^ Matches the beginning

$ Matches the end

. Matches any character except newline

| Means OR (Matches with any of the characters separated by it.

? Matches zero or one occurrence

* Any number of occurrences (including 0 occurrences)

+ One or more occurrences

{} Indicate the number of occurrences of a preceding regex to match.

() Enclose a group of Regex