how to use f in python 3 code example

Example 1: f string repr

# If you want to use repr in f-string use "!r"
# Normal behavior (using str)
>>> color = "blue\ngreen"
>>> day = datetime.date(2020, 6, 4)
>>> f"Color is {color} and day is {day}"
'Color is blue\ngreen and day is 2020-06-04'
# Alternate behavior (using repr)
>>> f"Color is {color!r} and day is {day!r}"
"Color is 'blue\\ngreen' and day is datetime.date(2020, 6, 4)"

Example 2: python fstring

#python3.6 is required
age = 12
name = "Simon"
print(f"Hi! My name is {name} and I am {age} years old")

Example 3: python f string

"""

An f-string stands for 'function-string' it's just used to work with 
strings more appropiately, they do the exact same job as concantenating
strings but are more efficient and readable.

"""
# Concantenating strings:

Age = "25"

print("I am "+Age+" years old.")

# Using f strings:

Age = 25

print(f"I am {Age} years old.")

# ^ notice the letter 'f' at the begining of the string.
# That defines the string as being an f-string.

# A third way of inputting variables into a string is by using
# .format()

Age = "25"

print("I am {} years old.".format(Age))

# If you had more than one variable:

Age = "25"
Name = "Jeff"

print("I am {} years old, and my name is {}.".format(Age,Name))