python 基础之第五天

###########window路径写法##########

In [1]: winpath = 'C:\tmp'

In [2]: print winpath
C: mp

In [3]: winpath = 'C:\\tmp'     #\t 会变成空格，所以需要加一个'\',转义符号

In [4]: winpath
Out[4]: 'C:\\tmp'

In [5]: print winpath
C:\tmp

In [6]: wpath = r'C:\tmp'         #或者加'r'

In [7]: print wpath
C:\tmp

##################内建函数####################

In [11]: hi = 'hello world'

In [12]: hi.capitalize()               #句首的单词首字母大写
Out[12]: 'Hello world'

In [13]: hi.title()                #报纸的标题，每个单子首字母大写
Out[13]: 'Hello World'        

In [14]: hi.center(20)             #居中 ，不够的用空格补上
Out[14]: ' hello world '

In [15]: hi.center(20,'+')
Out[15]: '++++hello world+++++'

In [16]: hi.ljust(20)           #左对齐
Out[16]: 'hello world　　　　　　 '

In [17]: hi.ljust(20,'#')
Out[17]: 'hello world#########'

In [18]: hi.rjust(20)          #右对齐
Out[18]: ' 　　　　 hello world'

In [19]: hi.rjust(20,'#')
Out[19]: '#########hello world'

In [20]: hi.count('l')         ####统计出现的次数，‘l’ 出现3次

Out[20]: 3

In [21]: hi.count('ll')     ####统计出现的次数，‘ll’ 出现1次
Out[21]: 1

In [22]: hi = 'hello world!'

In [25]: hi.startswith('h')         #########判断以什么开头，正确返回true,错误返回false
Out[25]: True

In [26]: hi.startswith('hello')
Out[26]: True

In [23]: hi.endswith('!')        #########判断以什么结尾，正确返回true,错误返回false
Out[23]: True

##########比较重要的#############

In [42]: hi = '  hello   world   '   

In [46]: hi.strip().split()      #strip() 去除字符串左右两边的空格，split() 什么都不加，默认以空格为分隔符
Out[46]: ['hello', 'world']    

In [47]: mylist = ['hello', 'world']

In [48]: '.'.join(mylist)     ###有切割，就有拼接
Out[48]: 'hello.world'

In [49]: '/'.join(mylist)
Out[49]: 'hello/world'

In [50]: ''.join(mylist)
Out[50]: 'helloworld'

In [51]: '\t'.join(mylist)
Out[51]: 'hello\tworld'

In [52]: ' '.join(mylist)
Out[52]: 'hello world'

In [53]: ' '.join(mylist)
Out[53]: 'hello world'

###########查看方式具体用法##############

In [54]: hi.
hi.capitalize  hi.endswith    hi.isalnum     hi.istitle     hi.lstrip      hi.rjust       hi.splitlines  hi.translate
hi.center      hi.expandtabs  hi.isalpha     hi.isupper     hi.partition   hi.rpartition  hi.startswith  hi.upper
hi.count       hi.find        hi.isdigit     hi.join        hi.replace     hi.rsplit      hi.strip       hi.zfill
hi.decode      hi.format      hi.islower     hi.ljust       hi.rfind       hi.rstrip      hi.swapcase
hi.encode      hi.index       hi.isspace     hi.lower       hi.rindex      hi.split       hi.title       

In [54]: hi.
hi.capitalize  hi.endswith    hi.isalnum     hi.istitle     hi.lstrip      hi.rjust       hi.splitlines  hi.translate
hi.center      hi.expandtabs  hi.isalpha     hi.isupper     hi.partition   hi.rpartition  hi.startswith  hi.upper
hi.count       hi.find        hi.isdigit     hi.join        hi.replace     hi.rsplit      hi.strip       hi.zfill
hi.decode      hi.format      hi.islower     hi.ljust       hi.rfind       hi.rstrip      hi.swapcase
hi.encode      hi.index       hi.isspace     hi.lower       hi.rindex      hi.split       hi.title       

In [54]: help(hi.format)
Help on built-in function format:

format(...)
    S.format(*args, **kwargs) -> string

In [55]: help(hi.replace)
Help on built-in function replace:

replace(...)
    S.replace(old, new[, count]) -> string

    Return a copy of string S with all occurrences of substring
    old replaced by new.  If the optional argument count is
    given, only the first count occurrences are replaced.

######字符串讲完了，现在开始列表（list）###############

1.list赋值与更新

In [56]: alist = [10,20,30,40]

In [57]: alist[1:3]
Out[57]: [20, 30]

In [58]: alist[1:3] = [2,3]

In [59]: alist
Out[59]: [10, 2, 3, 40]

[root@master script]# vim stack.py
#!/usr/bin/python
# coding:utf-8

stack = []

def pushit():
    item = raw_input('item:')
    stack.append(item)
def popit():
    stack.pop()

def viewit():
    print stack

def show_menu():
    CMDs = {'':pushit,'':popit,'':viewit}         ###这个方法很好用
    prompt = """(0) push it
(1) pop it
(2) view it
(3) quit
Please input your choice(0/1/2/3):"""

    while True:
        choice = raw_input(prompt).strip()[0]
        if choice not in '':
            print 'Invalid input,Try again'
            continue
        if choice == '':
            break
        """
        elif choice == '0':
            pushit()
        elif choice == '1':
            popit()
        elif choice == '2':
            viewit()
       """
        CMDs[choice]()          #字典型函数调用

if __name__ == '__main__':
    show_menu()