I'm trying to find the moving average of 20 numbers at a time, being read from a list. This moving average then needs to be inserted into the list. Here is my code:

```
inplis = file(r'table.csv','r').readlines()
outp = file(r'avg_volume.csv','w')
import math
emptyList = []
totalVolume = 0
counter = 0
for i in inplis:
rec = i.strip().split(",")
if rec[0] == 'Date':
rec.insert(1,emptyList)
continue
else:
counter = counter + len(i)
while counter == 20:
volume = float(rec[5])
totalVolume = totalVolume + volume
break
avgVolume = totalVolume/20
rec.insert(1,emptyList)
rec[1]= avgVolume
if counter!=20:
continue
import string
newStr = string.join(map(str,rec),",")+'\n'
outp.write(newStr)
outp.close()
```

There is obviously something wrong with the way the variable counter is being incremented but I don't know how to fix it.. I am trying to get it to count each i, and when it reaches 20, to find totalVolume and avgVolume. Volume is the 5th element of each i, where I am splitting the input file into one big list named inplis, which is then being split into invidual records named rec.

I'd appreciate any guidance, thank you!!