Python修改文本列对齐

letter                   ->             
LadderScore0                   ->       
LadderScore1                   ->       
LadderScore2                   ->       
LadderScore3                   ->       
LadderScore4                   ->       
LadderScore5                   ->       
LadderScore6                   ->       
LadderScore7                   ->       
LadderScore8                   ->       
LadderScore9                   ->       
WeeklyDoneCount0                   ->   
WeeklyDoneCount1                   ->   
WeeklyDoneCount2                   ->   
WeeklyDoneCount3                   ->   
WeeklyDoneCount4                   ->   
WeeklyDoneCount5                   ->   
WeeklyDoneCount6                   ->   
WeeklyDoneCount7                   ->   
WeeklyDoneCount8                   ->   
WeeklyDoneCount9                   ->   
LastFPS0                   ->           
LastFPS1                   ->           
LastFPS2                   ->           
LastFPS3                   ->           
LastFPS4                   ->           
LastFPS5                   ->           
LastFPS6                   ->           
LastFPS7                   ->           
LastFPS8                   ->           
LastFPS9                   ->

#!/usr/bin/env python
#coding:utf-8

import os
format = '%-*s%-*s\n'
file = open('a.txt','r')
f = open('file.txt','a')
all = ""
for i in file:
    i=i.split(' ')
    a = format % (20, i[0], 20, '->')
    all += a
    f.write(a)
f.close()
file.close()
print all