fileinput 模块替换文件内容使用求助

lonelysoul011

我想直接修改文件，将文件中以逗号','分割的第4列如果是空字段的话增加一个字符串 ，根据我写的python程序。能够实现将第4列空字段增加字符串，但是修改后，文件里面很多空行！求解！

源文件内容：a.txt

1. 0002,0012,1372377,qweqeqw,2013031100000728,647669,621661200000307,,,01,,10000.00000000000000,01,20130311,20130311,071620
   
2. 0002,0012,1363165,,2013031100000730,627706,622202400004358,,,01,,20000.00000000000000,01,20130311,20130311,071714
   
3. 0002,0012,1366224,,2013031100000939,663489,62226013100016x,,,01,,5000.000000000000000,01,20130311,20130311,073745
   
4. 0002,0012,1371530,,2013031100000940,682012,6225887835197,,,01,,20000.00000000000000,01,20130311,20130311,073746
   
5. 0002,0012,1353800,,2013031100000943,678769,6222980018821,,,01,,5000.000000000000000,01,20130311,20130311,073804
   
6. 0002,0012,1351230,cccddd,2013031100000943,678769,6222980018821,,,01,,5000.000000000000000,01,20130311,20130311,073804

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python 代码

1. #!/usr/bin/python
   
2. import fileinput
   
3. f = open('a.txt','r')
   
4. for  i  in  f:
   
5.      s = i.split(',')
   
6.      a = s[2]
   
7.      b = s[4]
   
8.      c = "some string"
   
9.      x = "%s,,%s" %(a,b)
   
10.      y = "%s,%s,%s" %(a,c,b)
    
11.      for line in fileinput.input(files='a.txt',inplace=1):
    
12.           print line.replace(x,y)
    
13.      fileinput.close()
    
14. 
    
15. f.close()

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执行后结果，部分（删除了很多空行，实际空行比下面的多）：

1. 0002,0012,1372377,qweqeqw,2013031100000728,647669,621661200000307,,,01,,10000.00000000000000,01,20130311,20130311,071620
   
2. 
   
3. 
   
4. 
   
5. 0002,0012,1363165,some string,2013031100000730,627706,622202400004358,,,01,,20000.00000000000000,01,20130311,20130311,071714
   
6. 
   
7. 
   
8. 
   
9. 0002,0012,1366224,some string,2013031100000939,663489,62226013100016x,,,01,,5000.000000000000000,01,20130311,20130311,073745

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HH106

回复 1# lonelysoul011

1. print line.replace(x,y)  ----> print line.replace(x,y),

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lonelysoul011

谢谢！按照该方法可以实现。回复 2# HH106