What's a typeable symbol to indicate “starts with” in a filter field?

Question

I am building a custom data grid control. The users do a lot of sorting and filtering. I want them to be able to do this with only the keyboard. Currently they can filter columns by typing in the column header. They can use symbols < > ! = to change the filter behavior to "less than", "greater than", not, and "is exactly". If they don't use a symbol it will filter down to rows that contain the string in the column. What's a good symbol that users can type on a standard en-us keyboard that would indicate that the users want to filter down to items that start with the string they type?

Answer 1

What you are describing is standard wildcard functionality, so you could append a * to the end of the start string (which is nice and standard); or perhaps + which could be fairly intuitive; or even % which is used by various flavours of SQL. As well as the Regular Expression ^ as described by Ben Brocka (which would go at the start of the string).

I don't think it's a good idea to mix conventions, though. Using a * at the beginning of the user entry to specify "starts with" may well confuse users who are used to conventional wildcards.

Edit following comments If full wildcard functionality is not supported, either a * could stop anything else being entered, or — probably better — a tooltip could pop-up saying that only trailing wildcards are supported (and then remove the offending letter).