Searching a list of tuples in python

I'm having a database (sqlite) of members of an organisation (less then 200 people). Now I'm trying to write an wx app that will search the databa开发者_开发百科se and return some contact information in a wx.grid. The app will have 2 TextCtrls, one for the first name and one for the last name. What I want to do here is make it possible to only write one or a few letters in the textctrls and that will start to return result. So, if I search "John Smith" I write "Jo" in the first TextCtrl and that will return every single John (or any one else having a name starting with those letters). It will not have an "search"-button, instead it will start searching whenever I press a key.

One way to solve this would be to search the database with like " SELECT * FROM contactlistview WHERE forname LIKE 'Jo%' " But that seems like a bad idea (very database heavy to do that for every keystroke?). Instead i thought of use fetchall() on a query like this " SELECT * FROM contactlistview " and then, for every keystroke, search the list of tuples that the query have returned. And that is my problem: Searching a list is not that difficult but how can I search a list of tuples with wildcards?

selected = [t for t in all_data if t[1].startswith('Jo')]

but, measure, don't guess. I think that in some cases, the query would be faster - specially if you have too many records. Maybe you should use a query on the first char, and then start using python-side filter, since you already have the results.

I think that generally, you shouldn't be afraid of giving tasks to a database. It's quite possible that the LIKE clause will be very fast. Sqlite is implemented in fairly robust C code, and will happily deal with queries like this.

If you're worried about sending too many requests, why not send a query once a user has entered a threshold of characters, such as three?

A list comprehension is probably the best way to return the result if you want to do added filtering.

If you are searching for a string matching the start using LIKE, eg 'abc%' (rather than anywhere in the string - '%abc%'), the search should be quite fast if you have an index on the field, as the db can use the index to help find the matches.