python文件练习

1. 把一个数字的list从小到大排序，然后写入文件，然后从文件中读取出来文件内容，然后反序，在追加到文件的下一行中
   

   import codecsf1 = codecs.open('4.txt','w')list = [12,4,8,20,54,35,60,100,72]list.sort()f1.write(str(list))f1.close()with open('4.txt') as f1:    print (f1.read())list.reverse()with open('4.txt','ab') as f1:    f1.write(str(list)+'\n')with open('4.txt') as f1:    print f1.read()

   
   
2. 分别把 string， list， tuple， dict写入到文件中
   

   string = 'abc'list = ['a', 'b', 'c']tuple = ('a', 'b', 'c')dict = {1:'a', 2:'b', 3:'c'}with open('4.txt', 'w') as f1:    f1.write(string+'\n')    f1.write(str(list)+'\n')    f1.write(str(tuple)+'\n')    f1.write(str(dict))with open('4.txt') as f1:    print f1.read()