string.format() with {} inside string as string - Python

Python's string.format() method is a powerful way to format strings. One of the useful features is that you can use {} as placeholders to insert values into strings. In this post, we will take a closer look at how this feature works.

Basic syntax

The basic syntax for using placeholders with string.format() is as follows:

string.format()

Inside the string, we can use {} as a placeholder. The value that we want to insert into the string will be passed as an argument to the format() method.

string.format(value)

Let's take a look at some examples.

name = "Alice"
age = 25
 
# Basic string formatting
print("My name is {} and I am {} years old".format(name, age))

In the above example, we have used {} as a placeholder inside the string. We have then passed two arguments to the format() method - name and age. These values are then inserted into the string at the corresponding placeholders.

Formatting numbers

We can also use placeholders to format numbers. We can specify the number of decimal places we want to display by using the : operator.

# Formatting numbers
x = 123.5678
print("The number is {:.2f}".format(x))

In this example, we have used :.2f as the format specifier. This means that we want to display the number with 2 decimal places.

Using placeholders inside placeholders

We can use placeholders inside other placeholders to create complex strings.

# Using placeholders inside placeholders
first_name = "John"
last_name = "Doe"
age = 30

print("My name is {0} {1} and I am {2} years old. My initials are {0[0]}.{1[0]}.".format(first_name, last_name, age))

In this example, we have used 0 and 1 as indices for the first_name and last_name values. We have also used {0[0]} and {1[0]} to access the first character of the first_name and last_name values.

Conclusion

Python's string.format() method is a powerful way to format strings. By using {} as placeholders, we can insert values into strings easily. We can also format numbers, and use placeholders inside other placeholders to create complex strings.