[Src: Python 2.5 Document]
1. if-statement
与C/C++不同的是，Python中 if 或 elif 要以 : 结尾
2. for-statement
iterates over the items of any sequence(a list or a string)
cat 3
window 6
defenestrate 12
若要修改序列中的内容，就只能在序列的副本上遍历。这里只能修改list的内容
['defenestrate', 'cat', 'window', 'defenestrate']
3. range()
a) range(10) ==> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
b) range(5, 10) ==> [5, 6, 7, 8, 9]
c) range(-10, -100, -30) ==> [-10, -40, -70]
4. else clause
Loop statements may have an else clause; it is executed when the loop terminates through exhaustion of the list (with for) or when the condition becomes false (with while), but not when the loop is terminated by a break statement.
即，当循环正常结束后，才会走到else语句中；如果循环被break掉，则跳过else
5. pass-statement
空语句，语法要求
6. Defining functions
def func_name(parameter1, parameter2,...)
函数参数的解析顺序：local symbol table -> global symbol table -> built-in symbol table
通常情况下只能在函数中访问global的变量，但无法修改其值。除非用global显式声明
a) Default Argument Values
从左到右的顺序，如果某个参数设有默认值，则其后的所有参数都必须设有默认值，与C++类似
while True:
ok = raw_input(prompt)
if ok in ('y', 'ye', 'yes'): return True
if ok in ('n', 'no', 'nop', 'nope'): return False
retries = retries - 1
if retries < 0: raise IOError, 'refusenik user'
print complaint
Default Value只会被赋值一次，因此可以对同一个函数，后续的调用会使用到前次调用的结果
L.append(a)
return L
print f(1)
print f(2)
print f(3)
# result
[1]
[1, 2]
[1, 2, 3]
消除此种影响的方法：
if L is None:
L = []
L.append(a)
return L
b) Keyword Arguments
允许以 "keyword = argument" 的方式传参。此时，传参的顺序不必遵守定义的顺序。No argument may receive a value more than once
注意：如果未以这种方式传参，则按照从左到右顺序赋值。一旦某个参数以keyword方式传参，则其后所有参数也必须采用此种方法
print "-- This parrot wouldn't", action,
print "if you put", voltage, "volts through it."
print "-- Lovely plumage, the", type
print "-- It's", state, "!"
# right
parrot(1000)
parrot(action = 'VOOOOOM', voltage = 1000000)
parrot('a thousand', state = 'pushing up the daisies')
parrot('a million', 'bereft of life', 'jump')
# wrong
parrot() # required argument missing
parrot(voltage=5.0, 'dead') # non-keyword argument following keyword
parrot(110, voltage=220) # duplicate value for argument
parrot(actor='John Cleese') # unknown keyword
**parameter: 接受一个dictionary(包含一组keyword arguments)
*parameter: the positional arguments beyond the formal parameter list。不能接受keyword arguments参数
如果两者一起使用，则*parameter必须出现在**parameter之前
print "-- Do you have any", kind, '?'
print "-- I'm sorry, we're all out of", kind
for arg in arguments: print arg
print '-'*40
keys = keywords.keys()
keys.sort()
for kw in keys: print kw, ':', keywords[kw]
#test
cheeseshop('Limburger', "It's very runny, sir.",
"It's really very, VERY runny, sir.",
client='John Cleese',
shopkeeper='Michael Palin',
sketch='Cheese Shop Sketch')
#resule
-- Do you have any Limburger ?
-- I'm sorry, we're all out of Limburger
It's very runny, sir.
It's really very, VERY runny, sir.
----------------------------------------
client : John Cleese
shopkeeper : Michael Palin
sketch : Cheese Shop Sketch
c) Arbitrary Argument Lists
file.write(format % args)
d) Unpacking Argument Lists
如果参数已经存于list或tuple中，则用*来展开参数
如果参数存于dictionary中，则用**
e) Lambda Forms
（与函数编程语言类似的功能？）像个函数