Reading and Writing lists to a file in Python
In this tutorial,we will learn how to read and write lists to a file in python with some cool and easy examples. In many situations,you might have to come up with this type of requirements.
Python programming language offers the standard methods write() and read() to read and write into the file. Reading and writing files is an important functionality in every programming language.
Reading and Writing Lists to a File in Python
To read and write lists to a file in Python, you can follow these steps:
*Writing a List to a File:*
1. Open a file in write mode using the open() function.
2. Use the write() method to write the list to the file. You can convert the list to a string using the str() function if the list contains non-string elements.
3. Close the file using the close() method.
Here’s an example code snippet to write a list to a file:
my_list = [1, 2, 3, 4, 5]
with open("my_list.txt", "w") as file:
file.write(str(my_list))
print("file written successfully")
The file is opened with the open() method in w mode within the with block. The with block ensures that once the entire block is executed the file is closed automatically.
If you run this program the output will be like this:
file written successfully
1. Open the file in read mode using the open() function.
2. Use the read() method to read the content of the file as a string.
3. Convert the string back to a list using the eval() function or by using libraries like json for more complex data structures.
4. Close the file.
Here’s an example code snippet to read a list from a file:
with open("my_list.txt", "r") as file:
content = file.read()
my_list = eval(content)
print(my_list)
In the above example we opened the file in read mode . The with block ensures that once the entire block is executed the file is closed automatically.
output: [1, 2, 3, 4, 5]