Trouble with Python lists

Question

The following code is intended to dump a long list of numbers from a csv into stat_by_symbol[symbol] so that I can call the list of numbers using each symbol as a key. For some reason, the code only seems to work for the first symbol. Can someone help me fix the code to work as intended? Many thanks.

with open('zzdata.csv', 'rb') as f:
 reader = csv.reader(f)
 reader.next()
 for symbol in symbols:#symbols in a list
 stat = []
 for row in reader:
 if symbol in row:
 stat.append(row[8])#stat becomes long list of numbers
 stat_by_symbol[symbol] = [stat]

Answer 1

The problem is that you can iterate over reader just once (therefore just the first symbol match).

Try this:

stat_by_symbol = {}
with open('zzdata.csv', 'rb') as f:
 reader = csv.reader(f)
 reader.next()
 for row in reader:
 for symbol in symbols:#symbols in a list
 if symbol in row:
 stat_by_symbol.setdefault(symbol, []).append(row[8])

• user1028861: Thanks! I also need to iterate over row[8] through row[27] such that all the numbers in row[8] are in place 0, all the numbers from row[9] in place 1, and so on. I tried adding: for i in range(8, 28): ...append(row[i]), but this procedure doesn't separate the lists of numbers like I need. Any help on this?
• eumiro: @johnjdc - update your question and add a better example of what you need
• user1028861: Just posted a new question: stackoverflow.com/questions/8517246/…