Introduction To Programming with Python-5
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The document is a class guide for teaching Python programming, focusing on modules, file input/output, and exception handling. It explains how to use Python modules, manipulate files with the open() function, and handle exceptions using try-except blocks. Additionally, it includes resources for further learning, such as a link to a Facebook group.
![Import Statement
You can use any Python source file as a module by executing an import
statement in some other Python source file. The import has the following
syntax:
import module1[, module2[,... moduleN]](https://image.slidesharecdn.com/introductiontoprogrammingwithpython-lecture5-140927102020-phpapp01/85/Introduction-To-Programming-with-Python-5-5-320.jpg)
![The open() Function
Before you can read or write a file, you have to open it using Python's built-in
open() function. This function creates a file object, which would be utilized
to call other support methods associated with it.
Syntax:
file object = open(file_name [, access_mode][, buffering])](https://image.slidesharecdn.com/introductiontoprogrammingwithpython-lecture5-140927102020-phpapp01/85/Introduction-To-Programming-with-Python-5-7-320.jpg)
![The read() & write() method
read() write()
The read() method reads a string from an
open file.
The write() method writes any string to an
open file.
fileObject.read([count]); fileObject.write(string);](https://image.slidesharecdn.com/introductiontoprogrammingwithpython-lecture5-140927102020-phpapp01/85/Introduction-To-Programming-with-Python-5-10-320.jpg)
Introduction To Programming with Python-5
- 1. Introduction to Programming with Python – Class 5 SYED FARJAD ZIA ZAIDI
- 2. Class Objectives Class Objective Understanding Python Modules, File I/O & Exceptions
- 3. Class Material •Chapter 7 - Python for Informatics: Exploring Information Reading
- 4. Python Modules Definition: A module is a file containing Python definitions and statements. The file name is the module name with the suffix .py appended.
- 5. Import Statement You can use any Python source file as a module by executing an import statement in some other Python source file. The import has the following syntax: import module1[, module2[,... moduleN]
- 6. Python Files I/O Until now, you have been reading and writing to the standard input and output. Now, we will see how to play with actual data files. Python provides basic functions and methods necessary to manipulate files by default. You can do your most of the file manipulation using a file object.
- 7. The open() Function Before you can read or write a file, you have to open it using Python's built-in open() function. This function creates a file object, which would be utilized to call other support methods associated with it. Syntax: file object = open(file_name [, access_mode][, buffering])
- 8. File attributes Attribute Description file.closed Returns true if file is closed, false otherwise. file.mode Returns access mode with which file was opened. file.name Returns name of the file. file.softspace Returns false if space explicitly required with print, true otherwise.
- 9. The close() Method: The close() method closes the file, and then no more operations on that file object can be performed.
- 10. The read() & write() method read() write() The read() method reads a string from an open file. The write() method writes any string to an open file. fileObject.read([count]); fileObject.write(string);
- 11. Exceptions In general, when a Python script encounters a situation that it can't cope with, it raises an exception. An exception is a Python object that represents an error. When a Python script raises an exception, it must either handle the exception immediately otherwise it would terminate and come out.
- 12. Handling exception If you have some suspicious code that may raise an exception, you can defend your program by placing the suspicious code in a try: block. After the try: block, include an except: statement, followed by a block of code which handles the problem as elegantly as possible.
- 13. Syntax for handling exceptions try: You do your operations here; ...................... except ExceptionI: If there is ExceptionI, then execute this block. except ExceptionII: If there is ExceptionII, then execute this block. ...................... else: If there is no exception then execute this block.
- 14. Assignment Link to Facebook Group: https://www.facebook.com/groups/introtopython.iccbs/