What is the usage of format in python

The usage of format in python is basic usage, specifying location, specifying variable name, formatting numbers, formatting date and time.

#The Format function is a built-in string formatting method in Python. It allows us to insert variables and other values ​​into strings and format them into a specific form. Using the format function, string concatenation and formatting needs can be handled more flexibly and readably in the code.

The basic syntax of formatting a string is to use {} as a placeholder, and then pass the actual variable or value to the placeholder through the format function. The formatted result replaces the placeholders to generate a new string.

The following are some common uses of the format function:

1. Basic usage:

The basic usage of the format function is to put variables or values ​​into {} placeholder, for example:

name = "Alice"

age = 25

print("My name is {} and I am {} years old .".format(name, age))

The output result is: My name is Alice and I am 25 years old.

2. Specify the location:

By specifying the position index, placeholders can be replaced in a fixed order. For example:

name = "Bob"

age = 30

print("My name is {1} and I am {0} years old.".format( age, name))

The output result is: My name is Bob and I am 30 years old.

3. Specify variable name:

If there are many placeholders, you can replace them by specifying variable names, which can make the code more readable and easier to maintain. For example:

name = "Charlie"

age = 35

print("My name is {name} and I am {age} years old.".format( name=name, age=age))

The output result is: My name is Charlie and I am 35 years old.

4. Format number:

The format function can be used to format the display of numbers, for example:

num = 3.14159

print("The value of pi is approximately {:.2f}.".format(num) )

The output result is: The value of pi is approximately 3.14.

5. Format date and time:

format function can also be used For formatting the display of date and time, for example:

from datetime import datetime

now = datetime.now()

print("Current date and time: { :%Y-%m-%d %H:%M:%S}".format(now))

The output result is: Current date and time: 2022-01-01 12:00:00

Summary:

The format function is a powerful string formatting method in Python, which can be used to replace placeholders and display them in a specific form variables and other values. By specifying positions, variable names, formatting numbers and dates, etc., you can achieve more flexible and readable string operations. In actual development, the format function is a very useful tool that can improve the readability and maintainability of the code. .

The above is the detailed content of What is the usage of format in python. For more information, please follow other related articles on the PHP Chinese website!