Uploading a Data .text File Into Python

Summary: in this tutorial, you acquire 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')                every bit                f:     lines = f.readlines()            
                          Code linguistic communication:              JavaScript              (              javascript              )                      

Steps for reading a text file in Python

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

• Get-go, open a text file for reading by using the open() function.
• 2nd, read text from the text file using the file read(), readline(), or readlines() method of the file object.
• Tertiary, shut the file using the file close() method.

1) open() role

The open() function has many parameters just y'all'll exist focusing on the get-go two.

            
              open(path_to_file, mode)            
          

The path_to_file parameter specifies the path to the text file.

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

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

For instance, if the file is readme.txt stored in the sample binder every bit the program, you need to specify the path to the file as c:/sample/readme.txt

The mode is an optional parameter. It'southward a string that specifies the mode in which you desire to open the file.

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

Mode	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 name is the-zen-of-python.txt stored in the aforementioned binder as the program, you utilize the following code:

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

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

2) Reading text methods

The file object provides y'all 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 have a pocket-size file and you desire to manipulate the whole text of that file.
• readline() – read the text file line by line and return all the lines equally strings.
• readlines() – read all the lines of the text file and render them every bit a list of strings.

3) shut() method

The file that you open up volition remain open until you close it using the shut() method.

It'south important to close the file that is no longer in use. If you don't close the file, the programme 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 close the file automatically without calling the shut() method, yous use 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 statement 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 string:

            
                              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 amend than implicit. Uncomplicated is amend than complex. ...                          
          

The following case 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')                equally                f:     lines = f.readlines()  count =                0                for                line                in                lines:     count +=                i                print(f'line {count}: {line}')                          
                          Code language:              JavaScript              (              javascript              )                      

Output:

            
              line 1: Cute is better than ugly.  line two: Explicit is better than implicit.  line 3: Simple is meliorate than complex. ...                          
          

The following instance shows how to use the readline() to read the text file line past line:

            
                              with                open('the-zen-of-python.txt')                every bit                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 circuitous.  Complex is improve than complicated. ...                          
          

A more concise fashion to read a text file line by line

The open() office returns a file object which is an iterable object. Therefore, y'all tin use a for loop to iterate over the lines of a text file as follows:

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

This is more curtailed fashion 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 elementary ASCII text file. And it's likely a UTF-viii 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-8' to the open() function to instruct information technology to expect UTF-8 characters from the file.

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

The post-obit shows how to loop through the quotes.txt file:

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

Output:

Summary

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