File Handling

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Previous Lesson

Many times, we might want to store information in files. Python allows us to easily, write, read, or change any information in a file. To access a file, you write open("fileName.txt", "mode"). In the first argument, you write the file name. Make sure that the file is in the same folder as your Python program. Otherwise, you would have to write the whole file path in the first argument. In the second, we have to tell Python what we want to do with the file. Do we want to read it, write it, both? Here are some examples:

• "r": read only
• "w": write only
• "a": append (change) only
• "r+": read and write
• "w+": write and read
• "a+": append and read

To read a file, you have to first open the file and save that in a variable, then use the .readlines() method to put the lines inside the file in a list. You can then print the list to read it.

•  Reading a File

Notice how there are some newline characters in the list. To remove it, we can use the .strip() method we discussed earlier to get rid of those characters. Here is an example:

•   Example

Now it looks clean.

To write in a file, you have two options, to make changes or to add something in a file (append), or to rewrite the entire file (write). Both writing and appending in a file uses the same methods but they are just two different types. If you want to write in a file that doesn't exist, it will create a new one for you. Here is an example of writing and appending in a file:

•  Writing in a File