Python中操作文件之write()方法的使用教程

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