# fileparse.py

#

# Exercise 3.3

import csv

def parse_csv(filename, select=None, types=None, has_headers=True, delimiter=','):

'''

Parse a CSV file into a list of records

'''

if select and not has_headers:

raise RuntimeError("select argument requires column headers")

with open(filename) as f:

rows = csv.reader(f, delimiter=delimiter)

if has_headers:

# Read the file headers

headers = next(rows)

if select:

indices = [headers.index(col) for col in select]

headers = select if has_headers else None

else:

indices = []

records = []

for rowno, row in enumerate(rows, 1):

if not row:

continue

if indices:

row = [ row[idx] for idx in indices]

if types:

try:

row = [func(val) for func, val in zip(types, row) ]

except ValueError as e:

print(f"Row {rowno}: Couldn't convert {row}")

print(f"Row {rowno}: Reason {e}")

if has_headers:

record = dict(zip(headers, row))

records.append(record)

else:

records.append(row)

return records