How can I make a list of str x match completely those in list y even when list x is longer than y? I want extra x values paired with None

Question

I am trying to set up a way to match a list of emails and a list of names as a tuple. However, I find that when it reaches the last name, those emails without a name to pair are not included in my tuple, how can I make these extra emails simply pair an empty string ("")?

Essentially, I have excel rows with the format, which I set into a pandas dataframe:

cust_ID	buyer_names	buyer_emails
1234	name 1; name 2; name 3	email1; email2; email3; email 4
.....	.....	......

I tried this:

# Set regular expression to catch emails
regex = r"[a-zA-Z0-9_.+-]*@[a-zA-Z0-9-]+.[a-zA-Z\.]*"

# Initialise empty list to add query ready emails
emails_query_format = []

# Iterate over retailer_id / emails template rows and append formatted emails to list
for i, row in df.iterrows():
    # Put all emails in the row into a list
    emails = re.findall(regex, df['additional_emails'][i])
    emails = [email.strip() for email in emails]
    
    # Put all additional buyers into a list
    buyer_names = row['additional_buyers']
    buyers = re.split(r";", buyer_names)
    buyers = [buyer.strip() for buyer in buyers]
    
    buyer_email_tuple = [*zip(emails, buyers)]

Eventually, after iterating over this tuple and putting them into the query format, like this:

  # For each pair I want to create a row with the formated 
  for email, buyer in buyer_email_tuple:

      # Here I am just putting it into a specific format to copy paste to query template
      query_format = "(" + str(row['retailer_id']) + "," + "'" + buyer + "'" + "," + "'" + \ 
      email + "'" + ")" + ","
      
      emails_query_format.append(query_format)

# New DataFrame to input query ready emails
query_df = pd.DataFrame(emails_query_format, columns=['query_ready'])

This way, the tuple does not include the extra 'email4'. Containers in the collections module came up in my mind but I didn't really see a clear way of using a defaultdict for this.

How can I make the tuple include email4 with simply a "" value as name paired to it?

Thanks in advance.

Answer 1

Solved the issue:

for idx in range(len(emails)):
    if idx <= len(buyers) -1:
        buyer_emails_tuple_list.append((buyers[idx], emails[idx]))
    elif idx > len(buyers) -1:
        buyer_emails_tuple_list.append(("", emails[idx]))

Now I can make sure that for those emails that have no corresponding buyer names I get them paired with an empty string as:

("", email4)