write()方法把字符串str写入文件。没有返回值。由于缓冲，字符串可能不实际显示文件，直到flush()或close()方法被调用。
语法
以下是write()方法的语法：
fileObject.write( str )
参数
- str -- 这是要被写入的文件中的字符串。
返回值
此方法不返回任何值。
例子
下面的例子显示write()方法的使用。
#!/usr/bin/python
# Open a file in write mode
fo = open("foo.txt", "rw+")
print "Name of the file: ", fo.name
# Assuming file has following 5 lines
# This is 1st line
# This is 2nd line
# This is 3rd line
# This is 4th line
# This is 5th line
str = "This is 6th line"
# Write a line at the end of the file.
fo.seek(0, 2)
line = fo.write( str )
# Now read complete file from beginning.
fo.seek(0,0)
for index in range(6):
line = fo.next()
print "Line No %d - %s" % (index, line)
# Close opend file
fo.close()
当我们运行上面的程序，它会产生以下结果：
Name of the file: foo.txt
Line No 0 - This is 1st line
Line No 1 - This is 2nd line
Line No 2 - This is 3rd line
Line No 3 - This is 4th line
Line No 4 - This is 5th line
Line No 5 - This is 6th line
