turning a list into pairs and writing them to a .db file with sqlite3

Question

I need to take a list of information such as:

my_list = ['a','1','b','2','c','3','d','4']

I need to write this information as pairs into two separate columns in a .db file with sqlite3.

| a | 1 |
| b | 2 |
| c | 3 |
| d | 4 |

sqlite3 will not allow me to pass a list as an argument so I tired:

connection = sqlite3.connect('mytest.db')
cursor = conn.cursor
cursor.execute('CREATE TABLE IF NOT EXISTS test(c1 TEXT, c2 TEXT)')

for i in my_list[0:len(my_list):2]:
    cursor.execute(INSERT INTO test (c1) VALUES (?)',(i,))
    connection.commit

for i in my_list[1:len(my_list):2]:
    cursor.execute(INSERT INTO test (c2) VALUES (?)',(i,))
    connection.commit

However, this is making the table appear like so:

|  a   | null |
|  b   | null |
|  c   | null |
|  d   | null |
| null |  1   |
| null |  2   |
| null |  3   |
| null |  4   |

score 1 · Accepted Answer · edited May 23 '17 at 12:16

1

You can do this with a pairwise iteration and executemany():

def pairwise(iterable):
    a = iter(iterable)
    return zip(a, a)

my_list = ['a','1','b','2','c','3','d','4']
cursor.executemany("""
    INSERT INTO 
        test (c1, c2) 
    VALUES 
        (?, ?)""", pairwise(my_list))
connection.commit()  # note: you need to call the commit method

edited May 23 '17 at 12:16

Community

1
1

answered Jan 02 '17 at 05:01

alecxe

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`literator = iter(my_list)` and `zip(literator, literator)` would be more efficient with space – inspectorG4dget Jan 02 '17 at 05:02
@inspectorG4dget you are right, just wanted to demonstrate the idea..thanks! – alecxe Jan 02 '17 at 05:02
I am confused what the difference is with inspectors code. – Chace Mcguyer Jan 02 '17 at 05:53

turning a list into pairs and writing them to a .db file with sqlite3

1 Answers1