what is f before string in python code example

Example 1: f string in python

# f-strings are short for formatted string like the following
# you can use the formatted string by two diffrent ways
# 1
name = "John Smith"
print(f"Hello, {name}")		# output = Hello, John Smith

# 2
name = "John Smith"
print("Hello, {}".format(name))		# output = Hello, John Smith

Example 2: in python f then string meaning

>>> import datetime
>>> name = 'Fred'
>>> age = 50
>>> anniversary = datetime.date(1991, 10, 12)
>>> f'My name is {name}, my age next year is {age+1}, my anniversary is {anniversary:%A, %B %d, %Y}.'
'My name is Fred, my age next year is 51, my anniversary is Saturday, October 12, 1991.'
>>> f'He said his name is {name!r}.'
"He said his name is 'Fred'."