Op 20090411

自由軟體工作坊 - Python 入門 Python tutorial Lloyd Huang [email_address]

簡介： Python 是一種泛用性的動態物件導向程式語言。自 1990 年代初由 Guido van Rossum ( 又常被稱為 GvR 或 BDFL) 創造至今已歷十數年發展，應用於系統管理、網路管理、網路傳輸程式、網頁程式開發、數值分析程式、圖形介面應用程式等方面，均有優秀的表現。本課程將會介紹這個程式語言的特性，以及目前廣為應用的部份。附帶簡短的實作教學，藉此一窺 Python 的能力，並提供一個學習的入門階。

今日內容：初學 Python 型別 Types ，運算 Operators 語法 Statements 函數 Functions 模組 Modules 物件 Classes 例外處理 Exceptions 常用 Python Modules Python Web CGI howto

Python 是什麼？ 1990 年代初由 Guido 開發的程式語言泛用性的動態物件導向程式語言應用於系統管理網路管理網路傳輸程式網頁程式開發數值分析程式圖形介面應用程式

誰在用 Python ？ Google Youtube BitTorrent NASA OLPC Plurk

Python 特色 ? 方便的 Python 快速的 Python 跨平台的 Python 高彈性的 Python

Python 語言特性 ? Script 特性語法強迫縮排直譯器動態語言特性物件導向跨平台 Python program is Python module Duck type 豐富的線上說明跟手冊

一分鐘學 python import os def do_func(): mylst=['hello','world',2,'python!'] for x in mylst: print x, a='ls -al' if a=='ls -al': do_func() os.system(a)

30 分鐘學 python Interpreter Python String Slices List Slices advanced for loop while loop def function (): help(), dir(),type()

六小時學 python ？你等一下就會知道了

日本 Ruby 會長高橋征義說輕量之人怠惰勤勉之人多數派 - 努力工作勤勉之人用的語言 Cobol C/C++ java 程式設計師在日本有兩類輕量之人用的語言 Ruby Perl Python 勤勉之人寫很多程式碼一個方法 1000 行輕量之人 1000 方法一行

可讀性語言 VS 唯寫性語言 #!/bin/sh # t2h {$1} html-ize a text file and save as foo.htm NL=" " cat $1 | sed -e 's/ at / at /g' | sed -e 's/[[:cntrl:]]/ /g'| sed -e 's/^[[:space:]]*$//g' | sed -e '/^$/{'"$NL"'N'"$NL"'/^$/D'"$NL"'}' | sed -e 's/^$/<UL><P>/g' | sed -e '/<P>$/{'"$NL"'N'"$NL"'s///'"$NL"'}'| sed -e 's/<P>[[:space:]]*"/<P><UL>"/' | sed -e 's/^[[:space:]]*-/<BR> -/g' | sed -e 's/http:[[:graph:]]*/<A HREF="&">[&]<A> /g'> foo.htm

可讀性語言 VS 唯寫性語言 echo -e "192.168.1.243 1000 T 192.168.1.243 1001 T 192.168.1.243 1002 L" | sed 's/100./0/' echo 'ä¸æ' |perl -p -e 's/&#(+);/chr($1)/eg'

初學 Python 下載 & 安裝 & 移除 google -> python download http://www.python.org/download/ 直譯器的使用 hello world python Python 教學文件 http://tinyurl.com/jubwx Python 學習手冊 http://tinyurl.com/c9ga73

型別 Types ，運算 Operators 數字 Numbers python 計算機 >>> a = 5 >>> a + 1 >>> a + _ >>> a + _ >>> a / 3 ; a / 3.0 字串 String +---+---+---+---+---+ | H | e | l | p | A | +---+---+---+---+---+ 0 1 2 3 4 5 -5 -4 -3 -2 -1 >>> stra='abc ' >>> stra + stra >>> stra * 3

型別 Types ，運算 Operators 列 List a=['a','b','c','d','e'] b=[1,2,3,4,5,6,'abc'] c=[a,b,a,b] len(c) ; len(a) ; len(b) 字典 Dict tel = {'jack': 4098, 'sape': 4139} tel['guido'] = 4127 del tel['sape'] tel['irv'] = 4127 tel tel.keys() tel.keys()[1] tel.has_key('guido')

語法 Statements - if else if elif else >>> x = int(raw_input("Please enter a number: ")) >>> if x < 0: ... x = 0 ... print 'Negative changed to zero' ... elif x == 0: ... print 'Zero' ... elif x == 1: ... print 'Single' ... else: ... print 'More' ...

語法 Statements - while while loop >>> a, b = 0, 1 >>> while b < 1000: ... print b, ... a, b = b, a+b ... 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987

語法 Statements - for loop for loop >>> a = ['cat', 'window', 'defenestrate'] >>> for x in a: ... print x, len(x) ... cat 3 window 6 defenestrate 12

語法 Statements - for range for range() >>> range(10) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> range(5, 10) [5, 6, 7, 8, 9] >>> range(0, 10, 3) [0, 3, 6, 9] >>> range(-10, -100, -30) [-10, -40, -70] >>> for i in range(1,10): ... print i, 1 2 3 4 5 6 7 8 9 >>> a = ['Mary', 'had', 'a', 'little', 'lamb'] >>> for i in range(len(a)): ... print i, a[i], "|", 0 Mary | 1 had | 2 a | 3 little | 4 lamb |

小試身手 99 乘法表 1x1=1 1x2=2 1x3=3..... 1x9=9 ..... 9x1=9 9x2=18 9x3=27 ... 9x9=81 提示 2 個 for 回圈 range(1,10) print "xxx %d"

函數 Functions def function(): >>> def fib(n): ... "Print a Fibonacci series up to n" ... a, b = 0, 1 ... while b < n: ... print b, ... a, b = b, a+b ... >>> fib(200) 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597

函數 Functions (n,m=0) def function(n,m=0): >>> def fib(n,m=0): ... "Print a Fibonacci series up to n" ... a, b = 0, 1 ... while b < n: ... if m < b: ... print b, ... a, b = b, a+b >>> fib(200) 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 >>> fib(200,8) >>> fib(m=10,n=200)

函數 Functions default value def function(): default value def ask_ok(prompt, retries=4, complaint='Yes or no, please!'): while 1: ok = raw_input(prompt) if ok in ('y', 'ye', 'yes'): return 1 if ok in ('n', 'no', 'nop', 'nope'): return 0 retries = retries - 1 if retries < 0: raise IOError, 'refusenik user' print complaint >>> ask_ok('Do you really want to quit?') >>> ask_ok('OK to overwrite the file?', 2)

函數 Functions return list def function(): return >>> def fib2(n): ... result = [] ... a, b = 0, 1 ... while b < n: ... result.append(b) ... a, b = b, a+b ... return result ... >>> f100 = fib2(100) # call it >>> f100 # write the result [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

函數 Functions return value def function(): return >>> def fib2(n,m): ... result = [] ... a, b = 0, 1 ... while b < n: ... result.append(b) ... a, b = b, a+b ... return result[-m:] ... >>> a , b = fib2(100,2) >>> print "a=%d b=%d" % (a,b) a=55 b=89

模組 Modules - Python modules Namespaces are one honking great idea -- let's do more of those! (Zen of Python) split your program into several files for easier maintenance . A module is just a python script with a .py suffix. Syntax: import modulename Your python script is already a module.

模組 Modules - fibo.py def fib(n): "write Fibonacci series up to n. hi This fib help menu" a, b = 0, 1 while b < n: print b, a, b = b, a+b def fib2(n): """ return Fibonacci series up to n hi This fib2 help menu """ a, b = 0, 1 result = [] while b < n: result.append(b); a, b = b, a+b return result if __name__ == '__main__': fib(100) f100=fib2(100) print f100

模組 Modules >>> import fibo >>> fibo.fib(1000) >>> fibo.fib2(1000) >>> fib=fibo.fib >>> fib(500) >>> fib2=fibo2.fib >>> fib2(500) >>> from fibo import fib, fib2 >>> fib(500) >>> fib2(500)

模組 Modules dir() help() >>> import fibo, sys >>> dir (fibo) >>> dir (fibo.fib) >>> dir (fibo.fib2) >>> help (fibo) >>> help (fib) >>> help (fib2) >>> dir (sys) >>> help (sys)

Python Modules HOWTO 寫個 modules 感受一下

物件 Classes class FClass: def setdata(self, value): self.data = value def display(self): print self.data x=FClass() y=FClass() x.setdata("hi all") y.setdata(7654321) x.display() y.display() x.data="rewrite data" x.display()

物件 Classes class SClass(FClass): def display(self): print 'SClass value display %s' % self.data z=SClass() z.setdata(42) z.display() x.display()

物件 Classes class TClass(SClass): def __init__(self, value): self.data = value def __add__(self, other): return TClass(self.data + other) def __mul__(self, other): self.data = self.data * other a=TClass("abc ") a.display() b = a + "xyz" b.display() a * 3 a.display()

例外處理 Exceptions except (TypeError,someError) : try: try_something() except: do_otherthing() else: do_closing() finally: try: try_something() finally: do_final()

例外處理 Exceptions #!/usr/bin/python while 1: try: x = int(raw_input("Please enter a number: ")) break except ValueError: print "Oops! That was no valid number. Try again..." print "You input number is %d" % (x)

例外處理 Exceptions >>> try: ... raise KeyboardInterrupt ... finally: ... print 'Goodbye, world!' ... Goodbye, world! Traceback (innermost last): File "<stdin>", line 2 KeyboardInterrupt

常用 Python Modules import os import re import string import time import sys import cgi import cgitb import urllib import telnetlib import ftplib

Lots of Python Modules….. Standard Python Modules http://www.python.org/doc/current/modindex.html PyPI:the Python Package Index: third-party Python packages. http://www.python.org/pypi

Python Web CGI howto CGI cgi-test.py #!/usr/bin/python import cgi, string, re, os, sys, time CGI_HTMLHEAD="Content-type: text/html" print CGI_HTMLHEAD print "<h3>" print time.ctime() print "</h3>"

Python Web CGI howto HTML setup.html DNS1 Server: <input type="text" id="dns1" name="dns1"/> <input type="submit" name="OK" value=" 確定 " /> CGI setup.py import cgi, string, re, os, sys, time CGI_HTMLHEAD="Content-type: text/html" print CGI_HTMLHEAD form = cgi.FieldStorage() if form.has_key('OK'): print "<h1>" print "%s" % (form['dns1'].value) print "</h1>"

其他線上文件 For beginer: http://wiki.python.org.tw/ThinkLikeComputerScientist http://wiki.python.org/moin/BeginnersGuide/NonProgrammers For experienced programmer: http://docs.python.org/tut/tut.html http://www.diveintopython.org/ http://wiki.python.org/moin/BeginnersGuide/Programmers Books for python: http://wiki.python.org/moin/PythonBooks

用屠宰場殺豬的方式煎雞蛋

Zen of Python python –c “import this” Simple is better than complex. (C++) Complex is better than complicated. (Java) Readability counts. (Perl) If the implementation is hard to explain, it's a bad idea. (Java framework like EJB) Explicit is better than implicit. (ruby on rails?) There should be one-- and preferably only one --obvious way to do it.

新手 : 你怎麼飛的 ??? 答 : import antigravity

謝謝收看 by Lloyd@ZZZzzz...

Op 20090411

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