Question

I have a small method to get one column from a MySQL database. It works, but it is returning a tuple like:

((1L,),(2L,),(3L,), ...)

I would like to get just a list [1L, 2L, 3L,...] (or even casting to int instead of long). I know I could write a loop to do it manually, but probably there is a fancier, more pythonish way of doing it.

This is the code of my function, just in case there is some way to get the MySQL result directly into a list and I haven’t heard of it!

def getFTPSentNotamIds():
    selectedIds = None
    try:
        # Connect to database
        db = MySQLdb.connect(host=Constants.database_host,
                             user=Constants.database_user,
                             passwd=Constants.database_passwd,
                             db=Constants.database_name)

        # Create a cursor to execute queries
        cursor = db.cursor()

        # Get every ObjectID of those objects which are Selected=1
        cursor.execute('SELECT ObjectID FROM MYTABLE WHERE Selected=1')

        # Get the NOTAMS
        selectedIds = cursor.fetchall()
    except MySQLdb.Error, e:
        print 'ERROR ' + str(e.args[0]) + ': ' + str(e.args[1])
    return selectedIds

Answer 1

each tuple in the returned value represent one row, if there is only 1 element in the row,

you can use list comprehension like following to get your list containing ObjectID’s as:

In [38]: l = ((1L,),(2L,),(3L,))

In [39]: [x[0] for x in l]
Out[39]: [1L, 2L, 3L]

In your function you can do return [x[0] for x in selectedIds]