Will somebody tell me.

Question

what is a substring.

Answer 1

it is a part of a string, for example:

given the string "this is a string"
here are some examples of substrings of it

"this"
"a string"
"is a str"

basically any sequence of letters that is also in the original string

Answer 2

a = "this is a string"
>>> a[4:]
' is a string'
>>> a[0:4]
'this'
>>> a[10:]
'string'
>>> a[::-1]
'gnirts a si siht'

Answer 3

Do you mean slicing?

Answer 4

A substring is a slice of a string, you use them when you need specific sections of a string