Python编程的简明入门教程分享

'''This is a multi-line string. This is the first line.
This is the second line.
"What's your name?," I asked.
He said "Bond, James Bond."
'''

if guess == number:
 print 'Congratulations, you guessed it.' # New block starts here
elif guess < number:
 print 'No, it is a little higher than that' # Another block
else:
 print 'No, it is a little lower than that'

while running:
 guess = int(raw_input('Enter an integer : '))
 if guess == number:
  print 'Congratulations, you guessed it.'
  running = False # this causes the while loop to stop
 elif guess < number:
  print 'No, it is a little higher than that'
 else:
  print 'No, it is a little lower than that'
else:
 print 'The while loop is over.'
 # Do anything else you want to do here

for i in range(1, 5):
 print i
else:
 print 'The for loop is over'

def sayHello():
 print 'Hello World!' # block belonging to the function
sayHello() # call the function

def printMax(a, b):
 if a > b:
  print a, 'is maximum'
 else:
  print b, 'is maximum'

def say(message, times = 1):
 print message * times

def func(a, b=5, c=10):
 print 'a is', a, 'and b is', b, 'and c is', c
func(3, 7)
func(25, c=24)
func(c=50, a=100)

import sys
print 'The command line arguments are:'
for i in sys.argv:
 print i

shoplist = ['apple', 'mango', 'carrot', 'banana']
print 'I have', len(shoplist),'items to purchase.'
print 'These items are:', # Notice the comma at end of the line
for item in shoplist:
 print item,
print '\nI also have to buy rice.'
shoplist.append('rice')
print 'My shopping list is now', shoplist
print 'I will sort my list now'
shoplist.sort()
print 'Sorted shopping list is', shoplist
print 'The first item I will buy is', shoplist[0]
olditem = shoplist[0]
del shoplist[0]
print 'I bought the', olditem
print 'My shopping list is now', shoplist

zoo = ('wolf', 'elephant', 'penguin')
print 'Number of animals in the zoo is', len(zoo)
new_zoo = ('monkey', 'dolphin', zoo)
print 'Number of animals in the new zoo is', len(new_zoo)
print 'All animals in new zoo are', new_zoo
print 'Animals brought from old zoo are', new_zoo[2]
print 'Last animal brought from old zoo is', new_zoo[2][2]

age = 22
name = 'Swaroop'
print '%s is %d years old' % (name, age)
print 'Why is %s playing with that python?' % name

ab = {  'Swaroop' : 'swaroopch@byteofpython.info',
    'Larry'  : 'larry@wall.org',
    'Matsumoto' : 'matz@ruby-lang.org',
    'Spammer' : 'spammer@hotmail.com'
  }
print "Swaroop's address is %s" % ab['Swaroop']
# Adding a key/value pair
ab['Guido'] = 'guido@python.org'
# Deleting a key/value pair
del ab['Spammer']
print '\nThere are %d contacts in the address-book\n' % len(ab)
for name, address in ab.items():
 print 'Contact %s at %s' % (name, address)
if 'Guido' in ab: # OR ab.has_key('Guido')
 print "\nGuido's address is %s" % ab['Guido']

shoplist = ['apple', 'mango', 'carrot', 'banana']
# Indexing or 'Subscription' operation
print 'Item 0 is', shoplist[0]
print 'Item 1 is', shoplist[1]
print 'Item -1 is', shoplist[-1]
print 'Item -2 is', shoplist[-2]
# Slicing on a list
print 'Item 1 to 3 is', shoplist[1:3]
print 'Item 2 to end is', shoplist[2:]
print 'Item 1 to -1 is', shoplist[1:-1]
print 'Item start to end is', shoplist[:]
# Slicing on a string
name = 'swaroop'
print 'characters 1 to 3 is', name[1:3]
print 'characters 2 to end is', name[2:]
print 'characters 1 to -1 is', name[1:-1]
print 'characters start to end is', name[:]

print 'Simple Assignment'
shoplist = ['apple', 'mango', 'carrot', 'banana']
mylist = shoplist # mylist is just another name pointing to the same object!
del shoplist[0]
print 'shoplist is', shoplist
print 'mylist is', mylist
# notice that both shoplist and mylist both print the same list without
# the 'apple' confirming that they point to the same object
print 'Copy by making a full slice'
mylist = shoplist[:] # make a copy by doing a full slice
del mylist[0] # remove first item
print 'shoplist is', shoplist
print 'mylist is', mylist
# notice that now the two lists are different

name = 'Swaroop' # This is a string object
if name.startswith('Swa'):
 print 'Yes, the string starts with "Swa"'
if 'a' in name:
 print 'Yes, it contains the string "a"'
if name.find('war') != -1:
 print 'Yes, it contains the string "war"'
delimiter = '_*_'
mylist = ['Brazil', 'Russia', 'India', 'China']
print delimiter.join(mylist) //用delimiter来连接mylist的字符

class Person:
 pass # An empty block
p = Person()
print p

class Person:
 def sayHi(self):
  print 'Hello, how are you?'
p = Person()
p.sayHi()

class Person:
 def __init__(self, name):
  self.name = name
 def sayHi(self):
  print 'Hello, my name is', self.name
p = Person('Swaroop')
p.sayHi()

class Person:
 '''Represents a person.'''
 population = 0
 def __init__(self, name):
  '''Initializes the person's data.'''
  self.name = name
  print '(Initializing %s)' % self.name
  # When this person is created, he/she
  # adds to the population
  Person.population += 1

class SchoolMember:
 '''Represents any school member.'''
 def __init__(self, name, age):
  self.name = name
class Teacher(SchoolMember):
 '''Represents a teacher.'''
 def __init__(self, name, age, salary):
  SchoolMember.__init__(self, name, age)
  self.salary = salary

f = file('poem.txt', 'w') # open for 'w'riting
f.write(poem) # write text to file
f.close() # close the file
f = file('poem.txt')
# if no mode is specified, 'r'ead mode is assumed by default
while True:
 line = f.readline()
 if len(line) == 0: # Zero length indicates EOF
  break
 print line,
 # Notice comma to avoid automatic newline added by Python
f.close() # close the file

import cPickle as p
#import pickle as p
shoplistfile = 'shoplist.data'
# the name of the file where we will store the object
shoplist = ['apple', 'mango', 'carrot']
# Write to the file
f = file(shoplistfile, 'w')
p.dump(shoplist, f) # dump the object to a file
f.close()
del shoplist # remove the shoplist
# Read back from the storage
f = file(shoplistfile)
storedlist = p.load(f)
print storedlist

import sys
try:
 s = raw_input('Enter something --> ')
except EOFError:
 print '\nWhy did you do an EOF on me?'
 sys.exit() # exit the program
except:
 print '\nSome error/exception occurred.'
 # here, we are not exiting the program
print 'Done'

class ShortInputException(Exception):
 '''A user-defined exception class.'''
 def __init__(self, length, atleast):
  Exception.__init__(self)
  self.length = length
  self.atleast = atleast
raise ShortInputException(len(s), 3)

import time
try:
 f = file('poem.txt')
 while True: # our usual file-reading idiom
  line = f.readline()
  if len(line) == 0:
   break
  time.sleep(2)
  print line,
finally:
 f.close()
 print 'Cleaning up...closed the file'