将空csv列值替换为零

所以我处理一个csv文件有缺失值。
我想要的脚本是：

So I'm dealing with a csv file that has missing values. What I want my script to is:

#!/usr/bin/python

import csv
import sys

#1. Place each record of a file in a list.
#2. Iterate thru each element of the list and get its length.
#3. If the length is less than one replace with value x.


reader = csv.reader(open(sys.argv[1], "rb"))
for row in reader:
    for x in row[:]:
                if len(x)< 1:
                         x = 0
                print x
print row

是一个数据的例子，我尝试它，理想情况下它应该工作在任何列lenghth

Here is an example of data, I trying it on, ideally it should work on any column lenghth

Before:
actnum,col2,col4
xxxxx ,    ,
xxxxx , 845   ,
xxxxx ,    ,545

After
actnum,col2,col4
xxxxx , 0  , 0
xxxxx , 845, 0
xxxxx , 0  ,545

更新以下是我现在的感谢：

Update Here is what I have now (thanks):

reader = csv.reader(open(sys.argv[1], "rb"))
for row in reader:
    for i, x in enumerate(row):
                if len(x)< 1:
                         x = row[i] = 0
print row

只是似乎出了一个记录，我将管道输出到一个新的文件在命令行。

However it only seems to out put one record, I will be piping the output to a new file on the command line.

更新3：好了现在我有相反的问题，我输出每个记录的重复。
为什么会发生这种情况？

Update 3: Ok now I have the opposite problem, I'm outputting duplicates of each records. Why is that happening?

After
actnum,col2,col4
actnum,col2,col4
xxxxx , 0  , 0
xxxxx , 0  , 0
xxxxx , 845, 0
xxxxx , 845, 0
xxxxx , 0  ,545
xxxxx , 0  ,545

Ok我修正了/ p>

Ok I fixed it (below) thanks you guys for your help.

#!/usr/bin/python

import csv
import sys

#1. Place each record of a file in a list.
#2. Iterate thru each element of the list and get its length.
#3. If the length is less than one replace with value x.


reader = csv.reader(open(sys.argv[1], "rb"))
for row in reader:
    for i, x in enumerate(row):
                if len(x)< 1:
                         x = row[i] = 0
    print ','.join(str(x) for x in row)