How to Read .data File in Python

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

TL;DR

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

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

Steps for reading a text file in Python

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

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

1) open() role

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

            
              open(path_to_file, manner)            
          

The path_to_file parameter specifies the path to the text file.

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

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

For instance, if the file is readme.txt stored in the sample folder as the programme, you lot demand to specify the path to the file equally c:/sample/readme.txt

The manner is an optional parameter. It's a string that specifies the fashion in which yous desire to open the file.

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

Manner	Description
'r'	Open for text file for reading text
'w'	Open a text file for writing text
'a'	Open a text file for appending text

For example, to open a file whose proper noun is the-zen-of-python.txt stored in the same folder as the programme, you lot use the following code:

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

The open() office 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 iii methods for reading text from a text file:

• read() – read all text from a file into a cord. This method is useful if you take a modest 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 render them as a list of strings.

iii) close() method

The file that you open will remain open until you close it using the close() method.

It'south important to close the file that is no longer in utilize. If you 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                .shut()            
                          Code linguistic communication:              CSS              (              css              )                      

To shut the file automatically without calling the close() method, yous use the with statement like this:

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

In practice, y'all'll apply the with statement to shut the file automatically.

Reading a text file examples

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

The post-obit instance illustrates how to utilize the read() method to read all the contents of the the-zen-of-python.txt file into a string:

            
                              with                open('the-zen-of-python.txt')                equally                f:     contents = f.read()     print(contents)            
                          Lawmaking language:              JavaScript              (              javascript              )                      

Output:

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

The following example 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 +=                ane                print(f'line {count}: {line}')                          
                          Code linguistic communication:              JavaScript              (              javascript              )                      

Output:

            
              line 1: Beautiful is better than ugly.  line 2: Explicit is ameliorate than implicit.  line iii: Uncomplicated is improve than circuitous. ...                          
          

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

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

Output:

            
              Explicit is better than implicit.  Uncomplicated is amend than complex.  Circuitous is ameliorate than complicated. ...                          
          

A more concise way 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 equally follows:

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

This is more concise way to read a text file line past 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 elementary ASCII text file. And it's likely a UTF-8 file that uses more than just the standard ASCII text characters.

To open a UTF-8 text file, you lot demand to laissez passer the encoding='utf-8' to the open() office to instruct it to look UTF-8 characters from the file.

For the sit-in, you'll use the following 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

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