python loop insert value in rows

Question

I have a dataframe containing address info such that

df
streetNumber   streetName   province   postalCode
120            ABC AVE          A          121345
20             ACD Street       A          231345
21             QWE AVE          B          234912
6              WDS Road         C          212344

I want to join these four columns into a single column called address to hold all address info at once. I use the following loop to join columns, but how can I insert the value in to the address column?

for index, row in df.iterrows():
    # try statements let us attempt something.
    try:
        address = ' '.join([row['streetNumber'], row['streetName'], 
                            row['province'], row['postalCode']])

Expected output

streetNumber   streetName   province   postalCode    address
120            ABC AVE          A          121345    120 ABC AVE A 121345
20             ACD Street       A          231345    20 ACD Street A 231345    
21             QWE AVE          B          234912    21 QWE AVE B 234912
6              WDS Road         C          212344    6 WDS Road C 212344