Reading from Files
Welcome to our Python programming course! Today, we’re diving into an essential skill: reading from files. Imagine you have a magical book filled with information. In Python, we can make our own magical books by creating files on our computers. But how do we read the information from these files? That’s what we’ll learn today!
1. Understanding Files: Before we start reading, let’s understand what a file is. Think of a file as a container that holds information, just like a book holds stories. Files can have different types of information, like text, numbers, or even pictures.
2. Opening a File: To read from a file, we need to open it first. It’s like unlocking the door to our magical book. We use the open() function in Python to do this. Here’s how:
file = open("my_file.txt", "r") # "r" means we're opening the file for reading
3. Reading from the File: Once the file is open, we can start reading from it. We have different methods to read, like read(), readline(), or readlines(). Let’s try them out:
# Reading the entire file
content = file.read()
print(content)
# Reading line by line
line = file.readline()
print(line)
# Reading all lines into a list
lines = file.readlines()
print(lines)
4. Closing the File: After we finish reading, it’s important to close the file, just like we close a book after reading. We do this using the close() method:
file.close()
Practice Questions:
- Question: What is a file in Python?Answer: A file is like a magical container that holds information, such as text or numbers.
- Question: How do we open a file for reading in Python?Answer: We use the
open()function, like this:file = open("my_file.txt", "r"). - Question: Why is it important to close a file after reading?Answer: Closing a file is important to free up resources and ensure that other programs can access it.
Practice Solutions:
- Question: Read the contents of a file named “data.txt” and print them.
Solution:
file = open("data.txt", "r")
content = file.read()
print(content)
file.close()
- Question: Read the first line from a file named “poem.txt” and print it.
Solution:
file = open("poem.txt", "r")
line = file.readline()
print(line)
file.close()
- Question: Read all lines from a file named “numbers.txt” and store them in a list, then print the list.
Solution:
file = open("numbers.txt", "r")
lines = file.readlines()
print(lines)
file.close()
Remember, practice makes perfect! Keep experimenting with reading from files to become a Python file wizard!