R How to Read Text File Line by Line

Table of Contents Hide

1. Steps to Read Text File in Python
   1. Python open() part
   2. Methods for Reading file contents
   3. Python close() role
2. Examples for Reading a Text file in Python
   1. Example i – Read the unabridged text file using the read() function
   2. Example 2 – Read the specific length of characters in a text file using the read() function
   3. Case iii – Read a unmarried line in a file using the readline() function
   4. Example 4- Read text file line by line using the readline() function
   5. Instance 5 – Read all the lines every bit a listing in a file using the readlines() function

Python provides built-in functions to perform file operations, such equally creating, reading, and writing files. There are mainly ii types of files that Python can handle, normal text files and binary files. In this tutorial, we will take a look at how to read text files in Python.

Steps to Read Text File in Python

In Python, to read a text file, you need to follow the below steps.

Footstep 1: The file needs to be opened for reading using the open() method and laissez passer a file path to the function.

Pace two: The next pace is to read the file, and this tin can exist achieved using several congenital-in methods such as read() , readline() , readlines() .

Pace iii: Once the read performance is performed, the text file must be airtight using the close() function.

Now that we take seen the steps to read the file content permit'due south sympathize each of these methods before getting into examples.

Python open() function

The open up() part opens the file if possible and returns the corresponding file object.

Syntax – open(file, manner='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)

The open() function has a lot of parameters. Let's have a expect at the necessary params for reading the text file. Information technology opens the file in a specified mode and returns a file object.

Parameters

• file – path like object which represents the file path
• mode (Optional) – The mode is an optional parameter. It's a string that specifies the mode in which you want to open the file.

Manner	Description
'r'	Open a file for read mode (default if fashion is non specified)
'w'	Open a file for writing. Python will create a new file if does non exist or truncates a file content if file exists
'x'	Open a file for exclusive creation.
'a'	Open a file for appending the text. Creates a new file if file does not be.
't'	Open a file in text mode. (default)
'b'	Open a file in binary manner.
'+'	Open a file for updating (reading and writing)

Example

              file = open('C:\hello.txt','r')            

Methods for Reading file contents

At that place are three ways to read data from a text file.

1. read() : The read() function returns the read bytes in the form of string. This method is useful when you have a pocket-size file, and you want to read the specified bytes or unabridged file and store information technology into a string variable.
2. readline() : The readline() function returns one line from a text file and retuns in the course of cord.
3. readlines() : The readlines() function reads all the lines from the text file and returns each line every bit a string chemical element in a list.

Python close() function

The file will remain open until you close the file using the close() function. It is a must and best practice to perform this performance subsequently reading the data from the file equally it frees upwards the memory space caused past that file. Otherwise, it may cause an unhandled exception.

Examples for Reading a Text file in Python

Example 1 – Read the entire text file using the read() part

In the below example, we are reading the entire text file using the read() method. The file can be opened in the read mode or in a text mode to read the data, and it tin be stored in the string variable.

              # Program to read the entire file using read() part file = open up("python.txt", "r") content = file.read() print(content) file.close()   # Program to read the entire file (absolute path) using read() part file = open("C:/Projects/Tryouts/python.txt", "r") content = file.read() print(content) file.shut()            

Output

              Dear User,  Welcome to Python Tutorial  Have a great learning !!!  Thank you            

Example 2 – Read the specific length of characters in a text file using the read() function

At that place are times where you need to read the specific bytes in a file. In that case, you tin can apply the read() office by specifying the bytes. The method volition output only the specified bytes of characters in a file, every bit shown below.

              # Program to read the specific length  # of characters in a file using read() function file = open up("python.txt", "r") content = file.read(twenty) print(content) file.close()                          

Output

              Dear User,  Welcome            

Example 3 – Read a single line in a file using the readline() part

If you lot desire to read a single line in a file, and so yous could attain this using readline() function. You lot likewise utilise this method to think specific bytes of characters in a line, similar to the read() method.

              # Program to read single line in a file using readline() function file = open("python.txt", "r") content = file.readline() print(content) file.close()            

Output

              Honey User,                          

Example 4- Read text file line past line using the readline() function

If y'all want to traverse the file line by line and output in any format, then you could use the while loop with the readline() method as shown below. This is the nearly effective style to read the text file line by line in Python.

              # Program to read all the lines in a file using readline() function file = open("python.txt", "r") while True: 	content=file.readline() 	if not content: 		interruption 	print(content) file.shut()                          

Output

              Dear User,  Welcome to Python Tutorial  Have a great learning !!!  Cheers            

Example 5 – Read all the lines equally a list in a file using the readlines() role

The readlines() method will read all the lines in the file and outputs in a list of strings, every bit shown below. Later on y'all can use the listing to traverse and excerpt the specified content from the list.

              # Program to read all the lines as a list in a file #  using readlines() part  file = open("python.txt", "r") content=file.readlines() print(content) file.shut()                          

Output

              ['Dear User,\n', 'Welcome to Python Tutorial\north', 'Take a corking learning !!!\n', 'Cheers']            

Related Tags

• shut(),
• mode,
• open(),
• read file content,
• read(),
• readline(),
• readlines()

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R How to Read Text File Line by Line

Source: https://itsmycode.com/python-read-text-file/

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