Python meetup 2
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The document discusses Python programming concepts like running Python programs, the Python virtual machine, importing and reloading modules, and taking input. It provides examples of running Python code from the interactive shell and command line, how the .py and .pyc files work, and importing modules and functions from different files. The document also presents a practice problem on generating the Fibonacci sequence.
![Input
standard input
a = “hello world”
print a
a = raw_input()
print a
sys.argv[1]
import sys
print sys.argv[1]
> python script1.py
script1.py](https://image.slidesharecdn.com/pythonmeetup2-140425125808-phpapp02/85/Python-meetup-2-9-320.jpg)
Python meetup 2
- 1. Python meetup -2 Vic Yang
- 2. How to run a program? Python Virtual Machine
- 3. Program Execution In interactive shell: print ‘hello world’ # hello world print 2 ** 100 # 1267650600228229491496703205376 In command line: python hello.py
- 4. Python Virtual Machine .py VS. .pyc 1. .py is the source code of Python 2. .pyc is the byte-compiled code of .py 3. .pyc can be executed in PVM
- 5. Python Virtual Machine .py .pyc PVM source byte code execution PVM is a huge loop that executes our code one by one.
- 6. .pyc A file contains byte-code interpreted from .py Boost the execution time. Rebuild automatically if .py changed. The text in .pyc file is not binary code.
- 7. Python Implementation CPython - ported from ANSI C, standard implementation. Jython - compiled Python code to Java byte- code and executed on JVM IronPython - similar as Jython implemented
- 9. Input standard input a = “hello world” print a a = raw_input() print a sys.argv[1] import sys print sys.argv[1] > python script1.py script1.py
- 10. Module import and reload script4.py print ‘hello world’ print 2 ** 100 title = ‘The Meaning of life’ IDLE >>>import script4 >>>reload(script4) >>>print script4.title
- 11. Module import and reload threenames.py a = ‘dead’ b = ‘parrot’ c = ‘sketch’ print a, b ,c IDLE >>>import three names >>>threenames.b, threenames.c >>>from threenames import a, b, c
- 12. Practice
- 14. Fibonacci sequence def fib(): x = 0 y = 1 while 1: yield x x, y = y, x + y ! g = fib() for i in range(9): print g.next()