How to Read a File Into a List Python

Summary: in this tutorial, you larn various ways to read text files in Python.

TL;DR

The following shows how to read all texts from the readme.txt file into a string:

            
                              with                open up('readme.txt')                as                f:     lines = f.readlines()            
                          Lawmaking language:              JavaScript              (              javascript              )                      

Steps for reading a text file in Python

To read a text file in Python, you follow these steps:

• First, open a text file for reading by using the open up() part.
• Second, read text from the text file using the file read(), readline(), or readlines() method of the file object.
• Third, close the file using the file shut() method.

1) open up() function

The open() function has many parameters but you'll be focusing on the first two.

            
              open up(path_to_file, fashion)            
          

The path_to_file parameter specifies the path to the text file.

If the file is in the same folder as the plan, you just demand to specify the proper noun of the file. Otherwise, you lot demand to specify the path to the file.

To specify the path to the file, you utilize the forward-slash ('/') fifty-fifty if y'all're working in Windows.

For instance, if the file is readme.txt stored in the sample folder as the plan, you need to specify the path to the file as c:/sample/readme.txt

The manner is an optional parameter. It's a cord that specifies the style in which you want to open up the file.

The following table shows available modes for opening a text file:

Mode	Clarification
'r'	Open up for text file for reading text
'w'	Open a text file for writing text
'a'	Open up a text file for appending text

For example, to open a file whose name is the-zen-of-python.txt stored in the same binder as the program, you utilize the following lawmaking:

            
                              f = open('the-zen-of-python.txt','r')            
                          Lawmaking linguistic communication:              JavaScript              (              javascript              )                      

The open() function returns a file object which you will use to read text from a text file.

2) Reading text methods

The file object provides you with 3 methods for reading text from a text file:

• read() – read all text from a file into a string. This method is useful if you have a small file and you want to dispense the whole text of that file.
• readline() – read the text file line by line and render all the lines equally strings.
• readlines() – read all the lines of the text file and return them as a list of strings.

3) shut() method

The file that you open will remain open until you close information technology using the shut() method.

It'due south of import to shut the file that is no longer in use. If yous don't shut the file, the program may crash or the file would be corrupted.

The following shows how to call the close() method to close the file:

            
                              f                .close()            
                          Code language:              CSS              (              css              )                      

To close the file automatically without calling the shut() method, you lot use the with argument similar this:

            
                              with                open(path_to_file)                as                f:     contents = f.readlines()            
                          Code linguistic communication:              JavaScript              (              javascript              )                      

In practice, you'll use the with argument to shut the file automatically.

Reading a text file examples

Nosotros'll utilize the-zen-of-python.txt file for the demonstration.

The following example illustrates how to utilise the read() method to read all the contents of the the-zen-of-python.txt file into a cord:

            
                              with                open('the-zen-of-python.txt')                as                f:     contents = f.read()     print(contents)            
                          Code linguistic communication:              JavaScript              (              javascript              )                      

Output:

            
              Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. ...                          
          

The post-obit example uses the readlines() method to read the text file and returns the file contents as a listing of strings:

            
              lines = []                with                open('the-zen-of-python.txt')                equally                f:     lines = f.readlines()  count =                0                for                line                in                lines:     count +=                1                print(f'line {count}: {line}')                          
                          Code linguistic communication:              JavaScript              (              javascript              )                      

Output:

            
              line 1: Beautiful is better than ugly.  line 2: Explicit is amend than implicit.  line 3: Simple is better than complex. ...                          
          

The post-obit example shows how to utilise the readline() to read the text file line past line:

            
                              with                open up('the-zen-of-python.txt')                as                f:     line = f.readline()                while                line:         line = f.readline()         print(line)            
                          Code language:              JavaScript              (              javascript              )                      

Output:

            
              Explicit is amend than implicit.  Simple is better than circuitous.  Complex is meliorate than complicated. ...                          
          

A more than concise manner to read a text file line past line

The open() function returns a file object which is an iterable object. Therefore, you can use a for loop to iterate over the lines of a text file as follows:

            
                              with                open('the-zen-of-python.txt')                every bit                f:                for                line                in                f:         print(line)            
                          Lawmaking language:              JavaScript              (              javascript              )                      

This is more curtailed style to read a text file line by line.

Read UTF-8 text files

The code in the previous examples works fine with ASCII text files. However, if you're dealing with other languages such as Japanese, Chinese, and Korean, the text file is non a simple ASCII text file. And information technology'south probable a UTF-8 file that uses more than just the standard ASCII text characters.

To open up a UTF-eight text file, you need to pass the encoding='utf-viii' to the open() function to instruct it to expect UTF-viii characters from the file.

For the sit-in, you'll use the post-obit quotes.txt file that contains some quotes in Japanese.

The following shows how to loop through the quotes.txt file:

            
                              with                open('quotes.txt', encoding='utf8')                as                f:                for                line                in                f:         print(line.strip())                          
                          Code language:              JavaScript              (              javascript              )                      

Output:

Summary

• Use the open() function with the 'r' mode to open a text file for reading.
• Utilize the read(), readline(), or readlines() method to read a text file.
• Always close a file afterward completing reading it using the close() method or the with argument.
• Use the encoding='utf-viii' to read the UTF-8 text file.

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Source: https://www.pythontutorial.net/python-basics/python-read-text-file/

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