match type with value in csv parsing function

[vinci]

Hello,

In the following code I do some parsing of files (csv):

#!/usr/bin/env python3

import csv

def parse_csv(filename, select=None, types=None):
    '''
    Parse a CSV file into a list of records
    '''
    with open(filename) as f:
        rows = csv.reader(f)

        # Read the file headers
        headers = next(rows)
        if select:
            indices = [ headers.index(colname) for colname in select ]
            headers = select
        else:
            indices = []

        records = []
        for row in rows:
            if not row:    # Skip rows with no data
                continue
            # Filter the row if specific columns were selected
            if indices:
                row = [ row[index] for index in indices ]
            if types:
                row = [ func(row) for func, val in zip(types, row) ]

            record = dict(zip(headers, row))
            records.append(record)

    return records

shares_held = parse_csv('../Data/portfoliodate.csv', select=['name', 'time'], types=[str, str])
print(shares_held)

My question is related to this sentence:

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

Is matching types with row essential here? If I replace it with this:

row = [ func(row) for func in types ]

the code seems to be behave identically, because you have to match the type and values anyway when calling the function (types=[str, str] ), otherwise it errors out.

Looking forward to your answers :)

[vinci]

What I've understood thus far is that this wouldn't/shouldn't work:

row = [ func(row) for func in types ]

I am applying the function (str) to the entire list and it doesn't make sense. Whereas iterating over the list should work.

The reason why I thought it was behaving differently was that I didn't actually test it correctly. Applying str on a list works, but applying anything else doesn't. And I was trying to test it by changing str to int (for a date format), and it didn't work and I thought this was expected behaviour, but I hadn't properly test int/float which wouldn't have worked either way.

[Larz60+]

please post sample (small) csv file