Reading and Writing to a File
Python allows you to read from and write to files using the built-in open()
function.
Reading a File
file = open("example.txt", "r") content = file.read() print(content) file.close()
Writing to a File
file = open("example.txt", "w") file.write("Hello, World!") file.close()
- Use
"r"
mode to read a file and"w"
mode to write to a file. Be sure to close the file after performing operations to free up resources.
Appending to a File
Appending allows you to add content to the end of a file without overwriting the existing data.
Example
file = open("example.txt", "a") file.write("Appending some text.") file.close()
- The
"a"
mode opens the file for appending. New content is added at the end of the file without altering existing content.
with
Context Manager
The with
statement is used to simplify file handling. It automatically closes the file when the block of code is exited, even if an error occurs.
Example
with open("example.txt", "r") as file: content = file.read() print(content)
- The
with
statement handles file closing automatically, ensuring that resources are properly freed.
Comma Separated Values (CSV) Files
CSV (Comma-Separated Values) files are commonly used for storing tabular data. Python’s csv
module makes it easy to work with CSV files.
Reading a CSV File
import csv with open("data.csv", "r") as file: reader = csv.reader(file) for row in reader: print(row)
Writing to a CSV File
import csv with open("data.csv", "w", newline='') as file: writer = csv.writer(file) writer.writerow(["Name", "Age", "City"]) writer.writerow(["Tala", 22, "Manila"])
- The
csv.reader
reads CSV files row by row, and thecsv.writer
writes rows to a CSV file. Thenewline=””
argument prevents extra blank lines in the output file.
JavaScript Object Notation (JSON) Files
JSON (JavaScript Object Notation) is a lightweight data format often used for data interchange between a server and a web application.
Reading a JSON File
import json with open("data.json", "r") as file: data = json.load(file) print(data)
Writing to a JSON File
import json data = { "name": "Tala", "age": 22, "city": "Manila" } with open("data.json", "w") as file: json.dump(data, file)
- The
json.load()
function reads JSON data from a file, whilejson.dump()
writes data to a JSON file.