including a variable in a string python code example

Example 1: how to use variables in string in python

#Use f-string
#Example:

x = 2
y = f'This is a string using variable x: {x}'
print(y)

#Output: 
#This is a string using variable x: 2

Example 2: insert into string python

def insert (source_str, insert_str, pos):
    return source_str[:pos]+insert_str+source_str[pos:]