Usage of read (), ReadLine (), and ReadLines () in Python read-write files

There are three kinds of functions in Python that read files:

• Read ()
• ReadLine ()
• ReadLines ()

However, what is the difference between them, when used in peacetime always encountered, summed up today.

0. Pre-work

First, create a new file Read.txt, for examples of actual effects

Hellowelcome to my worldyou are so clever !!!

1. Read ()

The read (size) method reads a size byte from the current location of the file, and the default (no parameter) indicates that the read to the end of the file is returned as a string object

The test procedure is as follows:

import oswith open(os.path.join(os.getcwd(), ‘read.txt‘)) as f:    content = f.read()    print(content)    print(type(content))

Here are two points to note:

1. I used OS-related operations, which eliminates the hassle of having to enter the full path of the file.

2. You have to form with open file as F: This habit, that is, after the operation is finished, let it automatically close the files.

Hellowelcome to my worldyou are so clever !!!<class ‘str‘>Process finished with exit code 0

2. ReadLine ()

Reads one line at a time, consumes less memory (for large files), and returns a String object

Test procedure:

import oswith open(os.path.join(os.getcwd(), ‘read.txt‘)) as f:    content = f.readline()    print(content)    print(type(content))

Output Result:

Hello<class ‘str‘>Process finished with exit code 0

3. ReadLines ()

Reads all the rows of the file, saves it in a list variable, and each behavior in the list is an element that returns a list object.

Test procedure:

import oswith open(os.path.join(os.getcwd(), ‘read.txt‘)) as f:    content = f.readlines()    print(content)    print(type(content))

Output Result:

[‘Hello\n‘, ‘welcome to my world\n‘, ‘1234\n‘, ‘you are so clever !!!‘]<class ‘list‘>Process finished with exit code 0

Usage of read (), ReadLine (), and ReadLines () in Python read-write files