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Python programming file handling mhhk.pptx
Files allow data to be persistently stored beyond a program's lifetime. The basic file operations in Python are open, close, read, and write. To open a file, the open() function is used, specifying the filename, mode (such as read 'r', write 'w', or append 'a'), and returning a file object. The file object's close() method finalizes any buffered operations when closing the file. Reading from an open file returns its contents as a sequence of lines, while writing clears the file's existing contents if opened in 'w' mode, or appends to the end if in 'a' mode.
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Python programming file handling mhhk.pptx
- 1. File I/O • Filesare persistent storage • Allow data to be stored beyond program lifetime • The basic operations on files are • open, close, read, write • Python treat files as sequence of lines • sequence operations work for the data read from files File handling
- 2. File I/O: openand close open(filename, mode) • While opening a file, you need to supply • The name of the file, including the path • The mode in which you want to open a file • Common modes are r (read), w (write), a (append) • Mode is optional, defaults to r • open(..) returns a file object • close() on the file object closes the file • finishes any buffered operations
- 3. File I/O: Example •Do some writing • How to do it? • see the next few slides
- 4. File I/O: read,write and append • Reading from an open file returns the contents of the file • as sequence of lines in the program • Writing to a file • IMPORTANT: If opened with mode 'w', clears the existing contents of the file • Use append mode ('a') to preserve the contents • Writing happens at the end