Python 读写文件

想要打开一个文件，既要读，也要写，就是先把文件内容读出来，然后往文件里写东西。

Python code

fileObj = open("test.ini","r+")
content = fileObj.read()
print content
fileObj.write("what's up")
fileObj.close()

这样写。。。居然报错：
test
Traceback (most recent call last):
File "D:\Proj\PythonProj\test.py", line 7, in <module>
fileObj.write("what's up")
IOError: [Errno 0] Error

肯定报错的，你以读的方式打开，然后用这对象去写是不行的。
你要以写的方式打开再操作

Python code

fileObj_r = open("test.ini","r+")
content = fileObj_r.read()
fileObj_r.close()
print content
fileObj_w = open("test.ini","w+")
fileObj_w.write("what's up")
fileObj_w.close()

#或者这样：
content = open("test.ini","r+").read()
print content
fileObj_w = open("test.ini","w+")
fileObj_w.write("what's up")
fileObj_w.close()

写只能用写方式打开的对象