python 语法基础3

#判断输入的数是否是数字

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.Xie
# @Time :2017/12/1 20:27
# @File :input.py


def fun():
    sth = raw_input("please input something:")
    try:
        if type(int(sth)) == type(1):
            print "%s is a number" % sth
    except ValueError:
        print "%s is not number" % sth


if __name__ == '__main__':
    fun()

执行结果：
please input something:htsjh
htsjh is not number
13 not number

#判断输入的参数中是不是纯数字

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.Xie
# @Time :2017/12/1 20:37
# @File :canshu.py


import sys


def isNum(s):
    for i in s:
        if i in '0123456789':
            pass
        else:
            print "%s is not a number" %s
            sys.exit()
    else:
        print "%s is a number" %s


if __name__ == '__main__':
    isNum(sys.argv[1])

执行结果：

567 is a number
125yrty is not a number

#打印系统PID

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.Xie
# @Time :2017/12/1 20:46
# @File :printpid.py

import os


def isNum(s):
    for i in s:
        if i in '0123456789':
            pass
        else:
            break

    else:
        print "%s is a number" %s


for i in os.listdir('/proc'):
    isNum(i)

执行结果：
[root@python day03]# python printpid.py 
1 is a number
2 is a number
3 is a number
4 is a number
5 is a number

函数传参

[root@ftp day03]# vi fun1_cp.py       

  1 #!/usr/bin/env python

  2

  3 import sys

  4

  5 def cp(sfname,dfname):

  6     src_fobj = open(sfname)

  7     dst_fobj = open(dfname,'w')

  8

  9     while True:

10         data = src_fobj.read(4096)

11         if not data:

12             break

13         dst_fobj.write(data)

14     src_fobj.close()

15     dst_fobj.close()

16

17 cp(sys.argv[1],sys.argv[2])

[root@ftp day03]# python fun1_cp.py /etc/hosts   /home/zhuji

[root@ftp day03]# ls /home

alvin  zhuji

[root@ftp day03]# cat /home/zhuji

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

In [9]:import string

In [10]: string.lowercase

Out[10]: 'abcdefghijklmnopqrstuvwxyz'

In [11]: string.__file__                                     #2个下划线

Out[11]: '/usr/lib64/python2.6/string.pyc'

#获得文件位置后，查看文件内容

[root@ftp day03]#vi /usr/lib64/python2.6/string.py

# Some strings for ctype-style character classification

whitespace = ' \t\n\r\v\f'

lowercase = 'abcdefghijklmnopqrstuvwxyz'

uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

letters = lowercase + uppercase

ascii_lowercase = lowercase

ascii_uppercase = uppercase

ascii_letters = ascii_lowercase + ascii_uppercase

digits = '0123456789'

hexdigits = digits + 'abcdef' + 'ABCDEF'

octdigits = '01234567'

punctuation = """!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""

printable = digits + letters + punctuation + whitespace

#函数的递归
#计算阶乘n! = 1 x 2 x 3 x ... x n

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author :Alvin.Xie
# @Time :2017/12/1 22:25
# @File :digui.py


def fact(n):
    if n == 1:
        return 1
    return n * fact(n - 1)


if __name__ == '__main__':
    print fact(1)
    print fact(5)

执行结果：
1
120