HTML table to CSV

Table2CSV.py

import sys

def generate_csv_data_from_html_table(html):
    csv_header = ""
    csv_rows = []
    rows = create_rows_from_trs(remove_tab_and_newline(html))
    for row in rows:
        if not row.find("<th>") == -1:
            csv_header = row.replace("<th>", "").replace("</th>", ",")
        elif not row.find("<td>") == -1:
            csv_rows.append(row.replace("<td>", "").replace("</td>", ","))
    return (csv_header, csv_rows)

def remove_tab_and_newline(string):
    return string.replace("\n", "").replace("\t", "")

def create_rows_from_trs(string):
    return string.replace("<table", "").replace("</table>", "") \
                 .replace("</tr>", "").split("<tr>")

if __name__ == '__main__':
    file = sys.argv[1]
    out_file = sys.argv[2]
    with open(file) as f:
        (header, rows) = generate_csv_data_from_html_table(f.read())
    with open(out_file, 'a') as out_f:
        # We want to make sure the file is empty, so beware!
        out_f.truncate()
        out_f.write("{0}\n".format(header))
        for row in rows:
            out_f.write("{0}\n".format(row))