String interpolation is the process to substitute a variable value inside a string by using placeholders. String interpolation provides dynamic usage of strings and text with different string values and variables. For example, to salute different persons a string interpolation can be used for different persons with different names. “Hello <name>” example is simple string interpolation where the <name> is substituted with different names in multiple usages.
String Interpolation with f-string
The f-string method is added with Python3.6 and provides very easy string interpolation by just using the string variables inside { } curly brackets. The variables should be used the same name as their definition names.
name="Ismail"
print(f"Hello {name}")
age="38"
print(f"Hello {name}. You are {age} years old.")String Interpolation with %-formatting
Python provides the % sign which is used for a long time in order to string interpolation. The %s is used to express string which is provided as a parameter to the print() method. The variables are provided inside the tuple which is replaced with every %s inside the string.
name="Ismail"
age="38"
print("Hello %s. You are %s years old."%(name,age))String Interpolation with Str.format()
Python provides the format() method for the String type. The string type can be a string variable or a string literal. The format() method accepts the variable names which are substituted with the {} inside the string.
name="Ismail"
age="38"
print("Hello {}. You are {} years old".format(name,age))String Interpolation with Template Strings
The template strings can be used for string interpolation. The string type provides the substitute() method which can be used to substitute identifiers inside a string. Identifiers start with the $ in order to define them.
from string import Template
name="Ismail"
age="38"
t = Template("Hello $name. You are $age years old")
print(t.substitute(name=name,age=age))