How To Read .data File In Python

Summary: in this tutorial, you learn various ways 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') every bit f: lines = f.readlines()

Code language: JavaScript ( javascript )

Steps for reading a text file in Python

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

First, open up 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.
Third, close the file using the file close() method.

i) open() function

The open() part has many parameters only yous'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 program, you just demand 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 forrard-slash ('/') even if you're working in Windows.

For case, if the file is readme.txt stored in the sample folder as the plan, yous need to specify the path to the file every bit c:/sample/readme.txt

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

The following tabular array shows available modes for opening a text file:

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

For case, to open a file whose proper name is the-zen-of-python.txt stored in the same folder every bit the plan, you utilize the following lawmaking:

f = open('the-zen-of-python.txt','r')

Code language: 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 y'all 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 accept a pocket-size file and yous desire to manipulate the whole text of that file.
readline() – read the text file line by line and return all the lines as strings.
readlines() – read all the lines of the text file and return them as a listing of strings.

iii) shut() method

The file that y'all open will remain open until yous shut it using the close() method.

It's of import to close the file that is no longer in use. If yous don't close the file, the programme may crash or the file would be corrupted.

The post-obit shows how to telephone call the close() method to close the file:

f .close()

Code language: CSS ( css )

To close the file automatically without calling the close() method, yous utilise the with argument similar this:

with open(path_to_file) as f: contents = f.readlines()

Code language: JavaScript ( javascript )

In exercise, yous'll employ the with statement to close the file automatically.

Reading a text file examples

Nosotros'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 up('the-zen-of-python.txt')                as                f:     contents = f.read()     print(contents)            
                          Code language:              JavaScript              (              javascript              )

Output:

Beautiful is better than ugly. Explicit is ameliorate 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 +=                1                print(f'line {count}: {line}')                          
                          Code language:              JavaScript              (              javascript              )

Output:

line one: Beautiful is better than ugly. line 2: Explicit is better than implicit. line three: Simple is meliorate than complex. ...

The following example shows how to use the readline() to read the text file line by line:

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

Output:

Explicit is ameliorate than implicit. Elementary is better than complex. Complex is amend than complicated. ...

A more concise way to read a text file line past line

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

with open up('the-zen-of-python.txt') as f: for line in f: impress(line)

Code language: JavaScript ( javascript )

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

Read UTF-viii text files

The code in the previous examples works fine with ASCII text files. Still, if yous'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 probable a UTF-eight file that uses more than than just the standard ASCII text characters.

To open a UTF-8 text file, you need to laissez passer the encoding='utf-viii' to the open() 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 following shows how to loop through the quotes.txt file:

with open('quotes.txt', encoding='utf8') equally f: for line in f: print(line.strip())

Code language: JavaScript ( javascript )

Output:

Summary

Employ the open() function with the 'r' style to open up a text file for reading.
Use the read(), readline(), or readlines() method to read a text file.
Always close a file afterwards completing reading information technology using the close() method or the with statement.
Use the encoding='utf-viii' to read the UTF-8 text file.