how to use format specifiers in python code example

Example 1: python string format

string_a = "Hello"
string_b = "Cena"

# Index based:
print("{0}, John {1}"
      .format(string_a, string_b))
# Object based:
print("{greeting}, John {last_name}"
      .format(greeting=string_a, last_name=string_b))

Example 2: formatting in python

# There are 3 different types of formatting. 
>>> name = "John"
>>> age = 19
>>> language = "python"
>>> print(f"{name} of age {age} programs in {language}") # Commonly used.
John of age 19 programs in python
>>> print("%s of age %d programs in %s" %(name, age, language)) # %s for str(), %d for int(), %f for float().
John of age 19 programs in python
>>> print("{} of age {} programs in {}".format(name, age, language)) # Values inside .format() will be placed inside curly braces repectively when no index is specified.
John of age 19 programs in python
>>> print("{2} of age {1} programs in {0}".format(name, age, language)) # Index can be specified inside of curly braces to switch the values from .format(val1, val2, val3).
python of age 19 programs in John