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| -rw-r--r-- | topics/maybe-monad.gmi | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/topics/maybe-monad.gmi b/topics/maybe-monad.gmi index b748ad5..d6f87f2 100644 --- a/topics/maybe-monad.gmi +++ b/topics/maybe-monad.gmi @@ -37,15 +37,16 @@ foo.map(lambda x: 1 + x) \ Finally, let's put all this together in a practical example using sql_query_mdict from genenetwork. Consider the following code using the DictCursor. The column foo may contain NULL values, and we need to check for them. ``` -with conn.cursor(MySQLdb.cursors.DictCursor) as cursor: - cursor.execute("SELECT foo FROM bar") - for row in cursor.fetchall(): - if row["foo"] is not None: - print(row["foo"]) +with database_connection() as conn: + with conn.cursor(MySQLdb.cursors.DictCursor) as cursor: + cursor.execute("SELECT foo FROM bar") + for row in cursor.fetchall(): + if row["foo"] is not None: + print(row["foo"]) ``` But, with sql_query_mdict, the row object is a MonadictDict where all values are monadic. We therefore do not need any special conditional checks. ``` -with database_connection() as conn +with database_connection() as conn: for row in sql_query_mdict(conn, "SELECT foo FROM bar"): row["foo"].bind(print) ``` |