Modules and Packages in Python_Basics.pdf
- 1. Modules and Packages in Python Tushar B. Kute, http://tusharkute.com
- 2. Lets see the example... • Modules are used to categorize code in Python into smaller part. • A module is simply a file, where classes, functions and variables are defined. • Grouping similar code into a single file makes it easy to access. • Types: – System modules – User defined modules
- 3. Advantages • Python provides the following advantages for using module: – 1) Reusability: Module can be used in some other python code. Hence it provides the facility of code reusability. – 2) Categorization: Similar type of attributes can be placed in one module.
- 4. Using system modules • import keyword • import as • from import
- 5. The import statement >>> import math >>> print math.sin(67) 0.855519978975 >>> print math.log(67) 4.20469261939 >>> print math.sqrt(67) 8.18535277187 >>> print math.pi 3.14159265359 >>> print math.e 2.71828182846
- 6. Import using alias >>> import math as m >>> print m.sin(90) 0.893996663601 >>> print m.log(90) 4.49980967033 >>> print m.sqrt(90) 9.48683298051 >>> print m.pi 3.14159265359 >>> print m.e 2.71828182846
- 7. Selective import • from..import statement is used to import particular attribute from a module. • In case you do not want whole of the module to be imported then you can use from ?import statement.
- 8. Example: >>> from math import sin, log, pi >>> print sin(55) 0.999755173359 >>> print log(55) 4.00733318523 >>> print pi 3.14159265359 >>> from math import * >>> print cos(55) 0.022126756262 >>> print e 2.71828182846
- 9. User defined modules • Any program stored in current working directory can be imported by import statement. • When such program (module) is imported, we can use all functions, classes and global variables from that program in your program. • The import, import...as and from...import will work in the same fashion.. • It creates a python compiled file with extension .pyc in current working directory
- 11. Python Package • A Package is simply a collection of similar modules, sub- packages etc.. • Steps to create and import Package: – 1) Create a directory, say Info – 2) Place different modules inside the directory. We are placing 3 modules msg1.py, msg2.py and msg3.py respectively and place corresponding codes in respective modules. Let us place msg1() in msg1.py, msg2() in msg2.py and msg3() in msg3.py. – 3) Create a file __init__.py which specifies attributes in each module. – 4) Import the package and use the attributes using package.
- 13. __init__.py
- 14. Using packages • Now create a new file outside of ‘info’ to import the given package. We can apply all import methods to use the package. • It creates four new .pyc files in info folder.
- 15. tushar@tusharkute.com Thank you This presentation is created using LibreOffice Impress 5.1.6.2, can be used freely as per GNU General Public License Web Resources http://mitu.co.in http://tusharkute.com /mITuSkillologies @mitu_group contact@mitu.co.in /company/mitu- skillologies