Introduction – Python File Handling
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Python File Handling helps to store program output permanently.
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Normally, output is lost after closing IDLE.
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File handling lets us save output in a file for later use.
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Data files store data that can be accessed anytime.
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It’s similar to saving a document like a CV for future reference.
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Python allows creating, storing, and accessing files easily.
- The types of files with which we have to go through are:-
- Text File
- Binary File
- CSV File
Relative and Absolute Path
- Relative path describe the location of a file relative to the working directory .
- Absolute path describe the location from the root directory.
How to work with File Handling?
- We have to follow the following points.
- Open a file
- First point to open a file , either a new file or a pre existing file, we may open the file for following purposes-
- Reading data from file – to read the content of the desired file.
- Writing data to file- to write the content into desired file
- Appending data to file- add some data in a pre-existing file
- Syntax for opening a file-
file = open("filename", "mode")
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filename → name/path of the file (e.g., “data.txt”)
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mode → defines how the file will be opened (read, write, append, etc.)
- Applying action on file
There are following file opening mode in a file handling in python:-
1. “r” – Read mode
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Opens file for reading only
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File must exist, otherwise error occurs
Syntax:
f = open("file.txt", "r")
2. “w” – Write mode
- Opens file for writing only
- Creates a new file if not exists
- Overwrites existing content
Syntax:
f = open("file.txt", "w")
3. “a” – Append mode
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Opens file for appending data
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Adds new data at the end of file
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Does not erase existing content
Syntax:
f = open("file.txt", "a")
4. “r+” – Read and Write mode
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Opens file for both reading and writing
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File must already exist
Syntax:
f = open("file.txt", "r+")
5. “w+” – Write and Read mode
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Opens file for reading and writing
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Creates new file if not exists
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Overwrites existing content
Syntax:
f = open("file.txt", "w+")
6. “a+” – Append and Read mode
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Opens file for appending and reading
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Creates file if not exists
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Cursor at end of file
Syntax:
f = open("file.txt", "a+")
- Close a file
A file can be closed by calling the close function using the file object.
Syntax:-
f.close()