How do you read the contents of a file in python?
Open a File on the ServerAssume we have the following file, located in the same folder as Python: Show
demofile.txt Hello! Welcome to demofile.txt To open the file, use the built-in The Example f = open("demofile.txt",
"r") Run Example » If the file is located in a different location, you will have to specify the file path, like this: ExampleOpen a file on a different location: f = open("D:\\myfiles\welcome.txt", "r") Run Example » Read Only Parts of the FileBy default the ExampleReturn the 5 first characters of the file: f = open("demofile.txt", "r") Run Example » Read LinesYou can
return one line by using the ExampleRead one line of the file: f = open("demofile.txt", "r") Run Example » By calling ExampleRead two lines of the file: f = open("demofile.txt",
"r") Run Example » By looping through the lines of the file, you can read the whole file, line by line: ExampleLoop through the file line by line: f = open("demofile.txt", "r") Run Example » Close FilesIt is a good practice to always close the file when you are done with it. ExampleClose the file when you are finish with it: f = open("demofile.txt", "r") Run Example » Note: You should always close your files, in some cases, due to buffering, changes made to a file may not show until you close the file. April 18, 2022 Files are everywhere: on
computers, mobile devices, and across the cloud. Working with files is essential for every programmer, regardless of which programming language you’re using. File handling is a mechanism for creating a file, writing data, and reading data from it. The good news is that Python is enriched with packages for handling different file types. In this tutorial, we’ll learn how to handle files of different types. However, we’ll focus more on
reading files with Python. After you finish this tutorial, you’ll know how to do the following: Let’s dive in. Before accessing the
contents of a file, we need to open the file. Python provides a built-in function that helps us open files in different modes. The First, let’s try the function by
opening a text file. Download the text file containing the Zen of Python, and store it in the same path as your code. In the code above, the In Python, we can use the The code above creates a context using the When the program reaches the end of the Notice that we have access to the However, it’s impossible to read from the file or write to the file. When a file is closed, any attempt to access its content leads to the following error: As we mentioned in the previous section, we need to specify the mode while opening a file. The following table shows the different file modes in Python: We can also specify opening a file in text mode,
The code above copies the Dataquest logo image and stores it in the same path. The Reading Text FilesThere are different ways to read text files. This section will review some of the useful methods for reading the content of text files. So far, we’ve learned the entire content of a file can be read with the
The simple code above reads the first 17 bytes of the zen_of_python.txt file and prints them out. Sometimes, it makes more sense to read the content of a text file one line at a time. In this case, we can use the
The code above returns the first line of the file. If we call the method one more time, it will return the second line in the file, etc., as follows:
This useful method helps us to read the entire file
incrementally. The following code outputs the entire file by iterating over it line by line until the file pointer that keeps track of where we’re reading or writing the file reaches the end of the file. When the
The code above reads the first line of the file outside the while loop and assigns it to the The other helpful method for reading text files is the
Let’s check the data type
of the
It’s a list of strings wherein each item in the list is one line of the text file. The
Reading CSV FilesSo far, we’ve learned how to work with regular text files. However, sometimes data comes in a CSV format, and it’s common for data professionals to retrieve required information and manipulate the content of CSV files. We’ll use the CSV module in this section. The CSV module provides helpful methods to read the comma-separated values stored in a CSV file. We’ll try it right now, but first, you need to download the
Each row of the CSV file forms a list wherein every item can be easily accessed, as follows:
It’s possible to use the name of the columns instead of using their indices, which is usually more convenient for developers. In this case, instead of using the
Reading JSON FilesAnother popular file format that we mainly use for storing and exchanging data is JSON. JSON stands for JavaScript Object Notation, and it allows us to store data with key-value pairs separated by commas. In this section, we’re going to load a JSON file and work with it as a JSON object — not as a text file. To do that, we need to import the JSON module. Then, in the
Let’s check the data type of the
Its data type is a dictionary. So we can access each piece of information stored in the JSON file with its key. Let’s see how we can retrieve data from it:
ConclusionThis tutorial discussed file handling in Python, focusing on reading the content of files. You learned about the open() built-in function, the with context manager, and how to read the common file types such as text, CSV, and JSON. How do I view the contents of a file in Python?To read, use the read ( r ) mode:. filename = '/Users/flavio/test.txt' file = open(filename, 'r') #or file = open(filename, mode='r'). content = file. read(). line = file. readline(). file. close(). How do you read a content of a file?There are several ways to read a plain text file in Java e.g. you can use FileReader, BufferedReader, or Scanner to read a text file.. Using BufferedReader class.. Using Scanner class.. Using File Reader class.. Reading the whole file in a List.. Read a text file as String.. How do you read the contents of a file into a string in Python?Generally, to read file content as a string, follow these steps.. Open file in read mode. Call inbuilt open() function with file path as argument. ... . Call read() method on the file object. read() method returns whole content of the file as a string.. Close the file by calling close() method on the file object.. How do I read a specific part of a file in Python?Method 1: fileobject.readlines()
A file object can be created in Python and then readlines() method can be invoked on this object to read lines into a stream. This method is preferred when a single line or a range of lines from a file needs to be accessed simultaneously.
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