/* while 是在有条件控制的情况下 进行的循环 */ [root@localhost test1]# vim 13.py //ADD #!/usr/bin/python n = 0 while True: if n == 10: break print n, ‘hello‘ n += 1 [root@localhost test1]# python 13.py 0 hello 1 hello 2 hello 3 hello 4 hello 5 hello 6 hello 7 hello 8 hello 9 hello
[root@localhost test1]# vim 14.py //ADD #!/usr/bin/python while True: print ‘hello‘ input = raw_input("Please input something.q for quit: ") if input == "q": break [root@localhost test1]# python 14.py hello Please input something.q for quit: e hello Please input something.q for quit: r hello Please input something.q for quit: t hello Please input something.q for quit: f hello Please input something.q for quit: q
[root@localhost test1]# vim 15.py //add #!/usr/bin/python x = ‘‘ while x != ‘q‘: print ‘hello‘ x = raw_input("Please input something, q for quit: ") /* 首先，要给x定义一个初始值， 然后再继续执行。 这里没有定义输入q后会有什么结果， 但是执行后，输入q则自动退出 */ [root@localhost test1]# python 15.py hello Please input something, q for quit: s hello Please input something, q for quit: s hello Please input something, q for quit: d hello Please input something, q for quit: f hello Please input something, q for quit: g hello Please input something, q for quit: q
/* 先创建一个文件 */
[root@localhost tmp]# cat 1.txt
1111
//先用一个变量定义，这个变量对应什么文件
In [1]: ll = open(‘/tmp/1.txt‘)
In [2]: ll
Out[2]: <open file ‘/tmp/1.txt‘, mode ‘r‘ at 0x99d81d8>
//将这个文件或变量打开，并赋予w权限
In [4]: ll = open(‘/tmp/1.txt‘, ‘w‘)
//写变量。括号里为写的内容，此处写的内容会覆盖原来的内容
In [5]: ll.write("aa")
[root@localhost tmp]# cat 1.txt
aa[root@localhost tmp]#
/* 有时，需要需要将变量关掉才可以执行看到改变 */
/* 再一次打开python的界面需要重新定义变量。*/
In [2]: ll = open(‘/tmp/1.txt‘)
In [3]: ll.read() //从最开始读
Out[3]: ‘aa‘
In [4]: ll.read() //当第二次读取时，指针已经读完了前面的内容，就只剩空了
Out[4]: ‘‘
/* 读取的具体内容 */ //1. 输入需要读取的 前几个字符 [root@localhost tmp]# cat 1.txt abc sjdh[root@localhost tmp]# In [1]: ll = open(‘/tmp/1.txt‘ , ‘r‘) In [2]: ll Out[2]: <open file ‘/tmp/1.txt‘, mode ‘r‘ at 0x9392180> In [3]: ll.read(2) Out[3]: ‘ab‘ // 2.读取一行 In [1]: ll = open(‘/tmp/1.txt‘) In [2]: ll.readline() Out[2]: ‘abc\n‘ // 3.读取多行（有多少行读多少行），并且返回一个list // 4. next() 可对一个文件一行一行的读取 In [5]: ll = open(‘/tmp/1.txt‘) In [6]: ll.readlines() Out[6]: [‘abc\n‘, ‘sjdh‘] In [1]: ll = open(‘/tmp/1.txt‘) In [2]: ll.next() Out[2]: ‘abc\n‘ In [3]: ll.next() Out[3]: ‘sjdh‘ In [4]: ll.next() --------------------------------------------------------------------------- StopIteration Traceback (most recent call last) <ipython-input-4-e9a4e3e4293f> in <module>() ----> 1 ll.next() StopIteration:
/* python脚本，对文件进行遍历 */
[root@localhost test1]# vim 16.py
//ADD
#!/usr/bin/python
ll = open(‘/tmp/1.txt‘)
for line in ll.readlines():
print line,
[root@localhost test1]# python 16.py
abc
sjdh
原文：http://www.cnblogs.com/frankielf0921/p/5842436.html