How to Read Data and Put in a List Python

Summary: in this tutorial, you learn 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('readme.txt')                as                f:     lines = f.readlines()            
                          Lawmaking linguistic communication:              JavaScript              (              javascript              )                      

Steps for reading a text file in Python

To read a text file in Python, y'all follow these steps:

• First, open a text file for reading by using the open() function.
• Second, read text from the text file using the file read(), readline(), or readlines() method of the file object.
• 3rd, close the file using the file close() method.

1) open() function

The open up() part has many parameters but you'll be focusing on the kickoff ii.

            
              open(path_to_file, manner)            
          

The path_to_file parameter specifies the path to the text file.

If the file is in the same binder equally the plan, you merely need to specify the proper name of the file. Otherwise, y'all demand to specify the path to the file.

To specify the path to the file, yous use the forwards-slash ('/') even if you're working in Windows.

For example, if the file is readme.txt stored in the sample folder as the program, y'all need to specify the path to the file as c:/sample/readme.txt

The mode is an optional parameter. It'south a cord that specifies the mode in which yous desire to open up the file.

The post-obit tabular array shows available modes for opening a text file:

Mode	Description
'r'	Open for text file for reading text
'due west'	Open a text file for writing text
'a'	Open a text file for appending text

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

            
                              f = open('the-zen-of-python.txt','r')            
                          Code language:              JavaScript              (              javascript              )                      

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

2) Reading text methods

The file object provides yous with three methods for reading text from a text file:

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

3) close() method

The file that you lot open volition remain open until y'all close information technology using the close() method.

It's of import to shut the file that is no longer in employ. If you don't close the file, the plan may crash or the file would be corrupted.

The post-obit 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 close() method, you utilize the with statement like this:

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

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

Reading a text file examples

We'll use the-zen-of-python.txt file for the demonstration.

The following example illustrates how to use 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 language:              JavaScript              (              javascript              )                      

Output:

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

The following instance uses the readlines() method to read the text file and returns the file contents as a list of strings:

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

Output:

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

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

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

Output:

            
              Explicit is better than implicit.  Simple is better than complex.  Complex is ameliorate than complicated. ...                          
          

A more than concise way to read a text file line by line

The open up() role returns a file object which is an iterable object. Therefore, yous tin can utilise 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 way 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 not a uncomplicated ASCII text file. And information technology's likely a UTF-eight file that uses more than than just the standard ASCII text characters.

To open a UTF-viii text file, you need to pass the encoding='utf-eight' to the open up() function to instruct it to expect UTF-8 characters from the file.

For the demonstration, you lot'll use the following quotes.txt file that contains some quotes in Japanese.

The post-obit 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 linguistic communication:              JavaScript              (              javascript              )                      

Output:

Summary

• Employ the open() part with the 'r' mode to open a text file for reading.
• Utilize the read(), readline(), or readlines() method to read a text file.
• Ever close a file afterward completing reading it using the shut() method or the with statement.
• Utilize the encoding='utf-eight' to read the UTF-viii text file.

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

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