import csv

data = []

def transform_row(row):
    # id = new count
    age = line[2]
    gender = line[3]
    url = line[4]

    return [
    #new count
    age,
    gender,
    url
    ]

# read csv file line by line
with open('data_sample.csv', 'r') as f:
    reader = csv.reader(f)

    """ bad try at ignoring the line with value -1
    for value in reader:
        if value == '-1':
            pass
        else:
            continue
    """

    # loop through each line in csv and transform
    for line in reader:
            data.append(transform_row(line))

# write a new csv file
with open('data_test.csv', 'w', newline='') as f:
    # define new csv writer
    writer = csv.writer(f, delimiter=',')

    # write a header row to our output.csv file
    writer.writerow([
        #'id', - new line count as id
        'age',
        'gender',
        'url'
    ])

    # write our data to the file
    writer.writerows(data)