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  • Core Python Programming笔记,Note

    >>> logfile=open('/tmp/mylog.txt','a')

    >>> print >> logfile, 'fatail error: invalid arguments'

    >>> logfile.close()

    >>>

    user=raw_input("please input your name:")

    Numbers:

    int

    long

    bool (True,False)

    float

    complex (6.23+1.5j)

    tuple

    1.元组,数组(是个线性结构,可以用整数索引)

    Lists [] and Tuples (): 

    hold any arbitrary number of arbitrary Python objects, the items are ordered

    and accessed via index offsets, similar to arrays, except that lists and tuples can store 

    different types of objects.

    Tuples can be thought of for now as "read-only" lists.

    Subsets can be taken with the slice operator ([] and [:]) in the same manner as strings.

    Dictionaries

    Dictionaries (or "dicts for short) are Python's mapping type and work like associative arrays

    or hashes found in perl.

    >>> aDict = {'host':'earth'}

    >>> aDict

    {'host': 'earth'}

    >>> aDict['port']=8080

    >>> aDict

    {'host': 'earth', 'port': 8080}

    >>> aDict.keys()

    ['host', 'port']

    >>> for key in aDict:

    ...     print key, aDict[key]

    ...

    host earth

    port 8080

    if expression1:

    if_suite

    elif expression2:

    elif_suite

    else:

    else_suite

    >>> while cnt<3:

    ...     print 'loop %d'%(cnt)

    ...     cnt+=1

    ...

    loop 0

    loop 1

    loop 2

    >>> for item in range(10):

    ...     print item

    >>> for item in ['e-mail','net-surfing','homework']:

    ...     print item

    ...

    e-mail

    net-surfing

    homework

    List Comprehensions:

    >>> squared = [x**2 for x in range(4)]

    >>> squared

    [0, 1, 4, 9]

    >>> for i in [x**2 for x in range(6)]:

    ...     print i

    ...

    0

    1

    4

    9

    16

    25

    Useful Built-In Functions for New Python Programmers

    dir([obj]),help([obj]),int(obj),len(obj),open(fn,mode),range([start,]stop[,step]),

    rraw_input(str),str(obj),type(obj)

    Typical Python file structure

    #!/usr/bin/env python		(1)Startup line (Unix)
    "this is a test module"		(2)Module documentation
    
    import sys
    import os			(3)Module imports
    
    debug = True			(4)(Global) Variable declarations
    
    class FooClass (object):
    	"Foo class"
    
    	pass			(5)Class declarations (if any)
    
    def test():
    	"test function"
    	foo = FooClass()
    	if debug:
    		print 'run test()'	(6)Funcation declarations(if any)
    
    if __name__ == '__main__':
    	test();			
    

      

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  • 原文地址:https://www.cnblogs.com/wucg/p/2145778.html
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