Python - String Formatting

String formatting is the process of building a string representation dynamically by inserting the value of numeric expressions in an already existing string. Python's string concatenation operator doesn't accept a non-string operand. Hence, Python offers following string formatting techniques −

Using % operator

The "%" (modulo) operator often referred to as the string formatting operator. It takes a format string along with a set of variables and combine them to create a string that contain values of the variables formatted in the specified way.

Example

To insert a string into a format string using the "%" operator, we use "%s" as shown in the below example −

name = "Tutorialspoint"
print("Welcome to %s!" % name)

It will produce the following output −

Welcome to Tutorialspoint!

Using format() method

It is a built-in method of str class. The format() method works by defining placeholders within a string using curly braces "{}". These placeholders are then replaced by the values specified in the method's arguments.

Example

In the below example, we are using format() method to insert values into a string dynamically.

str = "Welcome to {}"
print(str.format("Tutorialspoint"))

On running the above code, it will produce the following output −

Welcome to Tutorialspoint

Using f-string

The f-strings, also known as formatted string literals, is used to embed expressions inside string literals. The "f" in f-strings stands for formatted and prefixing it with strings creates an f-string. The curly braces "{}" within the string will then act as placeholders that is filled with variables, expressions, or function calls.

Example

The following example illustrates the working of f-strings with expressions.

item1_price = 2500
item2_price = 300
total = f'Total: {item1_price + item2_price}'
print(total)

The output of the above code is as follows −

Total: 2800

Using String Template class

The String Template class belongs to the string module and provides a way to format strings by using placeholders. Here, placeholders are defined by a dollar sign ($) followed by an identifier.

Example

The following example shows how to use Template class to format strings.

from string import Template

# Defining template string
str = "Hello and Welcome to $name !"

# Creating Template object
templateObj = Template(str)

# now provide values
new_str = templateObj.substitute(name="Tutorialspoint")
print(new_str)

It will produce the following output −

Hello and Welcome to Tutorialspoint !
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