Open & Write to Files

Creating a new file


The open command is used to open files but it is also used to create new files.

Look at the following code:

files1

Python will look in the same folder that you have saved this Python document (such as My Documents) for a file called Bookings.txt. If it can’t find a file with this exact name then it creates it.

The ‘wt’ stands for ‘write to’ and means you want to open the file in ‘write mode’ to edit its contents.

‘File’ is the variable name and can be called whatever you like.


Opening an existing file


To open an existing file you need to make sure it  it is saved in the same folder as your Python document (it should automatically be if you created it in Python like above). Make sure that you spell it right and use the correct extension (such as .txt or .text or .doc)


Writing to a File


After you have opened or created a file in write mode you can start saving data into it. A simple method of writing one line at a time is below:

files3

If you want to write on different lines then you will need to use the n command that we looked at all the way back in section 1:

files4.PNG

This is okay for small amounts of data but you may well want to use a list to hold more. We can use a list to write each item in the list to the file:

files5

In the example above the second write line is used to create a new line for each piece of data, which makes it much clearer when outputted later:

files6.PNG


Closing a file

Easy as pie, you just need to write .close() after your file variable, like:

files7.PNG


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