Python Learning Experience

One, advanced features:

1, slice: [Start:stop:step]

>>>l=range (6)>>>l[3,-1,2]resulte is [ 3]

2, Iteration

2.1 Press Itervalues ()

>>> d={1:2,2:3,3:4} for in D: ...      Print  1 22 33 4

2.2 Press Iteritems ()

 for inch D.iteritems ():      ... Print v ... (1, 2) (2, 3) (3, 4) returned as tuples

2.3 With index output: enumerate

 for  in Enumerate (['a','b','c' ]):...      Print I,value ... 0 A1 b2 C

2.4 Generator: The mechanism of the side loop computation, called the Generator (Generator), is useful for saving storage space, which is equivalent to the next in the list

def fib (max): ...     N,a,b=0,0,1      ...  while n<max: ...              yield b .....              b             =b,a+ ... n=n+1>>> fib (6) for in     fib (6): ... Print  112358

(ii), functional programming

1, higher order function: function name as parameter variable of method

def Add (x,y,abs):      ... return ABS (x) *abs (y)def  cut (     x,add): ... return x>>> cut (1, add) 0

2,map

The user input of the non-standard English name, into the first letter capitalization, other lowercase canonical name map (Lambda s:s.capitalize (), ['AC ','ac'][ac,ac]

Reduce

>>> L=map (Lambda s:s.capitalize (), ['ac','ac'  ])>>> reduce (lambda x,y:x+y,l)'AcAc'

Filter

>>>ImportMath>>>defIsprim (s): ... forIinchRange (2,int (math.sqrt (s) +1)):...             ifs%i==0: ...returnFalse ...returnTrue ...>>> Filter (Isprim,range (2,10))[2, 3, 5, 7]>>>Import Time>>>PrintTime.mktime (Time.localtime ())//Time Calculation1497605034.0

3,sorted x>y 1,x<y-1 x==y 0

Sorted ([1,3,2],Lambda x,y:y-x)//If y-x>0 is a two-digit exchange location, using bubbling sort [3, 2, 1]

4, Closure (Closure), using the Return function form:

def count ():    fs=[]     for in  Range (1,4)        def F (j):             def g ():                  return j*J            return  G        fs.append (f (i))    return FS  for inch count ():     Print I,j

5, anonymous function: Lambda

6, "Adorner" (Decorator): The method is enhanced, but there is no way to change

ImportFunctoolsdeflog (args):""""""Task="Pager"    defActual_log (func): @functools. Wraps (func)defWrapper (*args,**kw):Print '%s:%s ()'% (Task,func.__name__)//Two underlinereturnFunc (*args, * *kw)returnwrapperifHasattr (args,'__call__'):        returnactual_log (args)Else: Task=argsreturnActual_log@logdeff ():Pass@log ("Execute")defe ():Pass

5, Partial function

>>> max2=functool.partial (max,10)//10 aspart of the * args automatically added to the left >>> max2 (1,3,4,5)10
>>> def func (a,b,c):
>>> Print A,b,c
>>>func2=functools.partial (func,b=3) replacing key parameters
>>>func (1,c=4)
1 3 4

Python Learning Experience