Working with Files: Read from a Text File in Python

One of the fundamental operations in any language is to read a file and perform actions based on that.

You must've learned about Python's syntax, functions, and operators in the previous articles but in this article, you will learn about the basic operation of reading a text file in Python by understanding its procedure using an example program. Let's get started.

Reading from a text file in Python involves a few steps that you have to deploy to get the desired output. You will be using built-in functions like 'open()', 'read()', and 'close()'.

Here's a detailed explanation of how to do it:

1. Open the file: To read from a text file, you first need to open it using the 'open()' function. This function takes two arguments: the file path and the mode in which you want to open the file. To read from a file, you should pass the mode as 'r', which stands for read. Here's an example:

 >>> file_path = 'path/to/your/file.txt'
 >>> file = open(file_path, 'r')

2. Read the contents: Once you have opened the file, you can read its contents using various methods provided by the file object. The two commonly used methods are 'read()' and 'readlines()': a) 'read()': This method reads the entire content of the file and returns it as a singlestring. Here's an example:

 >>> content = file.read()
 >>> print(content)

 >>> lines = file.readlines()
 >>> for line in lines:
 >>>     print(line)

3. Close the file: After you have finished reading the file, it's good practice to close it using the 'close()' method. This will free up system resources. Here's an example:

 >>> file.close()

It's worth mentioning that opening a file using the 'open()' function requires you to manually close the file using 'close()'.

Alternatively, if you don't want to use 'close()' every time, you can use a context manager ('with' statement) to automatically handle the closing of the file. Here's an example:

 >>> file_path = 'path/to/your/file.txt'
 >>> with open(file_path, 'r') as file:
 >>> content = file.read()
 >>> print(content)

Since I used the 'with' statement here, I don't have to manually close the file, it will get closed automatically. Also, this method ensures that the file is properly closed even if an exception occurs.

NOTE: Remember to replace 'path/to/your/file.txt' with the actual file path on your system. Make sure to provide the correct path, including the file name and extension.

In conclusion, reading from a text file in Python is a fundamental skill that allows you to access and process data stored in external files. By utilizing the open() function and appropriate file object methods, such as read() or readlines(), you can retrieve the content of a file either as a single string or as individual lines.