DailyData.py reformat WikiPosit output

#!/usr/bin/env python

# dailydata.py
# Reformat the daily dataset feed spot price history so that it can
# be imported or copy and pasted into a spreadsheet.
# The source data omits weekends and holidays.
# After reformatting it, any missing days have data carried over from
# the previous business day.

from datetime import datetime, timedelta

fname = "dataset.csv"

fobj = open(fname, 'r')

lastDate = None
lastAmounts = None

for eachLine in fobj:
    cols = eachLine.strip().rstrip(',').split(',')

    if len(cols) < 2:
       # Blank probably, ingnore.
       continue

    curDateStr = cols[0]

    try:
       curDate = datetime.strptime(curDateStr, '%d-%b-%Y')
    except ValueError:
       # Probably a header row.  Must start with date. Skip it.
       continue

    # There should be just four columns (date, oil, gold, silver).
    assert len(cols) == 4

    while (lastDate <> None and curDate > (lastDate + timedelta(days=1))):
        # Missing a day.  Use the last amount again.
        lastDate = lastDate + timedelta(days=1)

        print ("{}, {: >8},{: >8},{: >8}".format(lastDate.strftime('%d-%b-%Y'), *lastAmounts))

    curAmounts = []

    for i in range(3):
        # For each of the data columns.
        # [col 0 has date, so col 1 is first value column].

        if cols[i + 1] == 'na':
            # Invalid data for the date.  Use previous day.
            curAmounts.append(lastAmounts[i])
        else:
            curAmounts.append(float(cols[i + 1]))

    print ("{}, {: >8},{: >8},{: >8}".format(curDate.strftime('%d-%b-%Y'), *curAmounts))

    lastDate = curDate
    lastAmounts = curAmounts

fobj.close()