Question

Does anyone know if there’s a way to automatically expand a list in Python, separated by commas? I’m writing some Python code that uses the MySQLdb library, and I’m trying to dynamically update a list of rows in a MySQL database with certain key values.

For instance, in the code below, I’d like to have the numeric values in the record_ids list expand into a SQL ‘IN‘ clause.

import MySQLdb record_ids = [ 23, 43, 71, 102, 121, 241 ]  mysql = MySQLdb.connect(user='username', passwd='secret', db='apps') mysql_cursor = mysql.cursor()  sqlStmt='UPDATE apps.sometable SET lastmod=SYSDATE() where rec_id in ( %s )'  mysql_cursor.execute( sqlStmt, record_ids ) mysql.commit() 

Any help would be appreciated!

Answer 1

try:

','.join( map(str, record_ids) ) 

','.join( list_of_strings ) joins a list of string by separating them with commas

if you have a list of numbers, map( str, list ) will convert it to a list of strings