python 复制文件流程

 例子代码：

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

old_file_name = raw_input("Please input you need copy's file name:" )

old_file = open(old_file_name,'r')

new_file = open('langwang.txt','w')

content = old_file.read()

new_file.write(content)

old_file.close()
new_file.close()

如果：hello.py  hello[复件].py 怎么实现呢？

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

old_file_name = raw_input("Please input you need copy's file name:" )

old_file = open(old_file_name,'r')

new_file_name = old_file_name.split('.')[0] + '[复件].' + old_file_name.split('.')[1]
new_file = open(new_file_name,'w')

content = old_file.read()

new_file.write(content)

old_file.close()
new_file.close()

还可以是：

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

old_file_name = raw_input("Please input you need copy's file name:" )

old_file = open(old_file_name,'r')

#new_file_name = old_file_name.split('.')[0] + '[复件].' + old_file_name.split('.')[1]
position = old_file_name.rfind(".")
new_file_name = old_file_name[:position] + '[复件]' + old_file_name[position:]
new_file = open(new_file_name,'w')

content = old_file.read()

new_file.write(content)

old_file.close()
new_file.close()

提示：

当一个文件非常大的时候，禁止使用read()读取，内存空间有限，用read（）读取大文件会出现memory err ，内存不足的情况

这种情况就没有解决办法吗？有的====》推荐使用如下代码：

[root@master script]# cat copy_file.py 
#!/usr/bin/python
# -*- coding:utf-8 -*-

old_file_name = raw_input("Please input you need copy's file name:" )

old_file = open(old_file_name,'r')

position = old_file_name.rfind(".")
new_file_name = old_file_name[:position] + '[复件]' + old_file_name[position:]

new_file = open(new_file_name,'w')
while True:
    content = old_file.read(1024)
    if not content:
        break
    new_file.write(content)

old_file.close()
new_file.close()

 ##########文件的位置############

In [17]: f = open("hello.py",'r')

In [18]: f.read()
Out[18]: "#!/usr/bin/python
#-*- coding:utf-8 -*-

i = 1

while i<=5:
    j = 1
    while j<=i:
        print '*',
        j+=1
    print ''
    i+=1

"

In [19]: f.seek(0,0)        ##指针，seek(0,0) 代表从头开始读

In [20]: f.read()
Out[20]: "#!/usr/bin/python
#-*- coding:utf-8 -*-

i = 1

while i<=5:
    j = 1
    while j<=i:
        print '*',
        j+=1
    print ''
    i+=1

"

In [21]: f.read()
Out[21]: ''

In [22]: f.tell()    ##指针的位置索引
Out[22]: 141

In [23]: f.read()
Out[23]: ''

In [24]: f.tell()
Out[24]: 141

In [25]: f.seek(0,0)

In [26]: f.tell()
Out[26]: 0